13G                     Page 1 of 5 Pages



                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                 SCHEDULE 13G


                                 (Rule 13d-102)


             INFORMATION STATEMENT PURSUANT TO RULES 13d-1 AND 13d-2


                   Under the Securities Exchange Act of 1934
                               (Amendment No.2)*



                              Unifirst Corporation
                                (Name of Issuer)


                       Common Stock $0.10 Value Per Share
                         (Title of Class of Securities)


                                    904708104
                                 (CUSIP Number)



Check the following box if a fee is  being paid with this statement [ ].


- ----------
*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).



CUSIP No.904708104                   13G                    Page 2 of 5 Pages



- --------------------------------------------------------------------------------
   1.  NAME OF REPORTING PERSON(S)
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON(S)

          Societe Generale Asset Management Corp. 13-3557071
       

- --------------------------------------------------------------------------------
   2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a)  [  ]
                                                             (b)  [  ]


- --------------------------------------------------------------------------------
   3.  SEC USE ONLY




- --------------------------------------------------------------------------------
   4.  CITIZENSHIP OR PLACE OF ORGANIZATION

          Delaware


- --------------------------------------------------------------------------------
   NUMBER OF      5.   SOLE VOTING POWER
     SHARES            
  BENEFICIALLY    --------------------------------------------------------------
    OWNED BY      6.   SHARED VOTING POWER
      EACH               799,500 Shared with its investment advisory client(s)
   REPORTING      --------------------------------------------------------------
     PERSON       7.   SOLE DISPOSITIVE POWER
      WITH        
                  --------------------------------------------------------------
                  8.   SHARED DISPOSITIVE POWER
                         799,500 Shared with its investment advisory client(s)
                         
- --------------------------------------------------------------------------------
   9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          799,500

- --------------------------------------------------------------------------------
  10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*



- --------------------------------------------------------------------------------
  11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

          10.13%

- --------------------------------------------------------------------------------
  12.  TYPE OF REPORTING PERSON*

          IA


- --------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       
                                       13G                   Page 3 of 5 Pages



Item 1.     (a)   Name of Issuer: 
                         Unifirst Corporation (the "Issuer").
                  ------------------------------------------------------------- 
            (b)   Address of Issuer's Principal Executive Offices:
                      68 Jonspin Road, Wilmington, Massachusetts 01887
                   
                  --------------------------------------------------------------
Item 2.     (a)   Name of Person Filing:
                         Societe Generale Asset Management Corp.,
                         a Delaware corporation (the "Adviser").
                  --------------------------------------------------------------
            (b)   Address of Principal Business Office, or if None, Residence:
                         The principal office of the Adviser is located at 
                         1221 Avenue of the Americas, New York, NY 10020
                  --------------------------------------------------------------
            (c)   Citizenship:
                         The Adviser is a Delaware corporation
                  --------------------------------------------------------------
            (d)   Title of Class of Securities:
                         Common Stock ($0.10 par value per share)(the "Shares").
                  --------------------------------------------------------------
            (e)   CUSIP Number:
                                   904708104
                               -------------------------------------------------
Item 3.     If this statement  is filed  pursuant to Rules  13d-1(b), or  
            13d-2(b), check whether the person filing is a:

            (a)   [ ]   Broker or Dealer  registered under Section  15 of  the
                        Act, 

            (b)   [ ]   Bank as defined in Section 3(a)(6) of the Act,

            (c)   [ ]   Insurance Company  as defined  in Section  3(a)(19) of
                        the Act,

            (d)   [ ]   Investment Company registered under  Section 8 of  the
                        Investment Company Act,

            (e)   [X]   Investment Adviser registered under Section 203 of the
                        Investment Advisers Act of 1940,

            (f)   [ ]   Employee Benefit Plan,  Pension Fund which is  subject
                        to the  provisions of  the Employee Retirement  Income
                        Security Act of  1974 or Endowment  Fund; see  Section
                        240.13d-1(b)(ii)(F); see Item 7,

            (g)   [ ]   Parent  Holding  Company, in  accordance  with Section
                        240.13d-1(b)(1)(ii)(G); see Item 7,

            (h)   [ ]   Group, in accordance with Section
                        240.13d-1(b)(1)(ii)(H).



                                      
                                      13-G                   Page 4 of 5 Pages



Item 4.     Ownership.


            If more than five percent of the class is owned, indicate:

            (a) Amount beneficially owned:  799,500 Shares
               
            (b) Percent of class:   10.13% of the outstanding Shares.
                
            (c) Number of shares as to which such person has:

                  (i) Sole power to vote or to direct the vote: None
                                                              
                  (ii) Shared power to vote or to direct the vote: 799,500
                                                                 
                  (iii) Sole power to dispose or to direct the disposition of
                        
                         None

                  (iv) Shared power to dispose or to direct the disposition of

                       799,500, and

            (d) Shares which there is a right to acquire: None.
                                                         

Item 5.     Ownership of Five Percent or Less of a Class.

                    Not Applicable.

Item 6.     Ownership of More Than Five Percent on Behalf of Another Person.

                    Not Applicable.

Item 7.     Identification and Classification of the Subsidiary which Acquired
            the Security Being Reported on By the Parent Holding Company.

                    Not Applicable.

Item 8.     Identification and Classification of Members of the Group.

                    Not Applicable.

Item 9.     Notice of Dissolution of Group.

                    Not Applicable.

Item 10.    Certification.

            By  signing  below  I  certify  that,  to the  best  of  my
            knowledge and belief, the securities referred to above were acquired
            in the  ordinary  course of business  and were not  acquired for the
            purpose of and do not have the effect of changing or influencing the
            control of the issuer of such  securities  and were not  acquired in
            connection with or as a participant in any  transaction  having such
            purpose or effect.


                                       13G                    Page 5 of 5 Pages


                                  Signature.


            After  reasonable  inquiry  and to the  best  of my  knowledge  and
            belief,  I  certify  that the  information  set  forth in this
            statement is true, complete and correct.


Date:     January 28, 1998

SOCIETE GENERALE ASSET MANAGEMENT CORP.
By:       /s/Jean-Marie Eveillard
Title:    Jean-Marie Eveillard, President