Abstract: Disclosed is a copolymer resin composition including a lactic acid copolymer, the lactic acid copolymer containing monomer units represented by the following chemical formulas [1], [2], and [3], wherein a content of a monomer unit represented by the chemical formula [3] is 50 mol % or more and 95 mol % or less, a weight-average molecular weight of the lactic acid copolymer is 20,000 or more and 1,000,000 or less, and a deflection temperature of the lactic acid copolymer under load is 65° C. or higher and 100° C. or lower at a bending stress of 1.80 MPa.