A film or sheet composed of a resin composition comprising: a poly lactic acid; an acidic functional group-modified olefinic polymer including an acidic functional group and having an acid value of 10 to 70 mg KOH/g and a weight average molecular weight of 10,000 to 80,000, wherein the acid value of the acidic functional group-modified olefinic polymer is determined by neutralization titration in accordance with Japanese Industrial Standard K0070-1992, and the weight average molecular weight of the acidic functional group-modified olefinic polymer is determined as described in the specification; a tetrafluoroethylene polymer; and a dicarboxylic acid ester-containing plasticizer of General Formula, where B is a 1,2-phenylene group or -CH 2 (CH 2) m CH 2 - where m is an integer of 0 to 6; and each of Aa and Ab is independently selected from to where a compound in which both Aa and Ab are is excluded: C 6 H 5 -(Ac)- where Ac is an alkylene group having 1 to 4 carbon atoms; (Ae)-(Ad-O) n - where Ad is an alkylene group having 1 to 5 carbon atoms, Ae is an alkyl group having 1 to 7 carbon atoms, and n is an integer of 1 to 4; and an alkyl group having 1 to 14 carbon atoms, the acidic functional group-modified olefinic polymer being included in an amount of 0.1 to 10.0 parts by weight based on 100 parts by weight of the poly lactic acid, the tetrafluoroethylene polymer being included in an amount of 0.5 to 15.0 parts by weight based on 100 parts by weight of the poly lactic acid, and the dicarboxylic acid ester-containing plasticizer being included in an amount of 8 parts by weight or more and less than 40 parts by weight based on 100 parts by weight of the poly lactic acid. a poly lactic acid; an acidic functional group-modified olefinic polymer including an acidic functional group and having an acid value of 10 to 70 mg KOH/g and a weight average molecular weight of 10,000 to 80,000, wherein the acid value of the acidic functional group-modified olefinic polymer is determined by neutralization titration in accordance with Japanese Industrial Standard K0070-1992, and the weight average molecular weight of the acidic functional group-modified olefinic polymer is determined as described in the specification; a tetrafluoroethylene polymer; and a dicarboxylic acid ester-containing plasticizer of General Formula, where B is a 1,2-phenylene group or -CH 2 (CH 2) m CH 2 - where m is an integer of 0 to 6; and each of Aa and Ab is independently selected from to where a compound in which both Aa and Ab are is excluded: C 6 H 5 -(Ac)- where Ac is an alkylene group having 1 to 4 carbon atoms; (Ae)-(Ad-O) n - where Ad is an alkylene group having 1 to 5 carbon atoms, Ae is an alkyl group having 1 to 7 carbon atoms, and n is an integer of 1 to 4; and an alkyl group having 1 to 14 carbon atoms, the acidic functional group-modified olefinic polymer being included in an amount of 0.1 to 10.0 parts by weight based on 100 parts by weight of the poly lactic acid, the tetrafluoroethylene polymer being included in an amount of 0.5 to 15.0 parts by weight based on 100 parts by weight of the poly lactic acid, and the dicarboxylic acid ester-containing plasticizer being included in an amount of 8 parts by weight or more and less than 40 parts by weight based on 100 parts by weight of the poly lactic acid.