To provide a thermoplastic resin composition which excels in thermal stability and reduces the amount of formaldehyde generated in molding and in product usage to thereby improve a work environment in molding and a product usage environment, and which retains excellent biodegradability, reduces load on ambient surroundings and ensures excellent mechanical properties such as impact resistance.

The thermoplastic resin composition contains (C) a hydrazide compound and/or a disemicarbazide compound in (A) a polyoxymethylene resin and (B) a resin component comprising an aliphatic polyester resin containing 0-30 mol% of an aliphatic oxycarboxylic acid unit, 35-50 mol% of an aliphatic diol unit and 35-50 mol% of an aliphatic dicarboxylic acid unit. A resin molding obtained by molding the composition is also provided.