Some polyurethane resin compositions are used to seal objects such as electric and electronic components in order to provide protection from condensation and pollutants. Such polyurethane resin compositions are often used under high-temperature environments. Thus, the present invention provides a polyurethane resin composition that has high thermal resistance. The polyurethane resin composition isobtained by reacting a hydroxyl group-containing compound (A) with an isocyanate group-containing compound (B) and contains an anti-oxidant (C) having an alkyl-thio group.