A polyacetal resin composition comprises a polyacetal resin and a hetero atom-containing aliphatic carboxylic acid hydrazide. The proportion of the hetero atom-containing aliphatic carboxylic acid hydrazide may be about 0.001 to 20 parts by weight relative to 100 parts by weight of the polyacetal resin. The polyacetal resin composition may further comprise at least one member selected from the group consisting of an antioxidant, a heat stabilizer, a processing stabilizer, a weather (light)-resistant stabilizer, an impact resistance improver, a gloss control agent, an agent for improving sliding property, a coloring agent, and a filler. Such a resin composition improves stability of the polyacetal resin and inhibits formaldehyde emission.