Provided is a polyacetal resin composition obtained from a starting composition comprising a polyacetal resin, a hydrazine derivative, and a compound for lowering the melting point of the hydrazine derivative, wherein the mixture of the hydrazine derivative and the compound satisfies the conditions of T1 < T2 and T1 < T3. where T1 is the maximum temperature of the endothermic peak representing the maximum endothermic capacity when, by means of DSC, the mixture is subjected to heating and cooling by a predetermined temperature program and then the mixture is heated at a predetermined speed until melting occurs, and T2 and T3 are similarly the maximum temperature of the endothermic peak representing the maximum endothermic capacity of the hydrazine derivative and polyacetal resin, respectively.