To provide a resin composition having practically sufficient heat resistance, biodegradability, mechanical characteristics, and in particular, excellent toughness.

In the polyoxymethylene resin composition consisting of a polyoxymethylene copolymer, polyglycolic acid and polylactic acid, a weight ratio (polyoxymethylene copolymer/polyglycolic acid) of the polyoxymethylene copolymer to the polyglycolic acid is from 20/80 to 80/20, and a weight ratio (a total amount of polyoxymethylene copolymer and polyglycolic acid/polylactic acid) of the total amount of the polyoxymethylene copolymer and the polyglycolic acid to the polylactic acid is from 100/0 to 66/34.