The polyacetal resin composition contains about 0.01-10 parts by weight of a
glyoxyldiureide compound per 100 parts by weight of polyacetal resin. The glyoxyldiureide
compound includes glyoxyldiureide and its derivatives (metal salts etc.). Optionally,
about 0.01-10 parts by weight of a basic nitrogen-containing compound is further
added. The basic nitrogen-containing compound includes melamine, melamine resin,
and polyamide resin. Further, an antioxidant may be further added. The above composition
contributes to stability, particularly heat stability, of polyacetal resin and
suppression of emission of formaldehyde.