About 0.001 to 1 part by weight of a phenol component (B1) and/or about 0.001 to 10 parts by weight of an amino acid (B2) are added relative to 100 parts by weight of a polyacetal resin (A) to prepare a polyacetal resin composition. The phenol component (B1) may be a novolak phenol-series resin, a phenol aralkyl-series resin, a polyvinyl phenol-series resin, a polyhydric phenol, a polyphenol, a catechin compound, or a lignin. The amino acid (B2) may be an .alpha.-amino acid, a .beta.-amino acid, a .gamma.-amino acid, a .delta.-amino acid, or a derivative of an amino acid. The polyacetal resin composition may further contain an antioxidant, a heat stabilizer, a processing stabilizer, a weather (light)-resistant stabilizer, or a coloring agent. The polyacetal resin composition ensures marked inhibition of formaldehyde emission.