Provided is a purified lactic acid-glycolic acid copolymer, preferably in the form of powder, having a reduced content of dimers such as residual lactide and glycolide that can be produced by a simple industrial process without the use of any high-shear special device. Further provided is a high-purity lactic acid-glycolic acid copolymer which has small amounts of dimers such as residual lactide and glycolide and small amounts of a low-molecular weight lactic acid-glycolic acid copolymer or a salt thereof and which has a small ratio of weight average molecular weight to number average molecular weight (Mw/Mn). The copolymer can be produced in accordance with a defined process.
