Disclosed is a polyurethane resin composition containing a urethane prepolymer having an active hydrogen group and a polyisocyanate, or a polyurethane resin composition alternatively containing a urethane prepolymer having an isocyanate group and an active hydrogen compound. The urethane prepolymer having an active hydrogen group or an isocyanate group is obtained by reacting a bi- or multi-functional active hydrogen compound with an allophanate group-containing polyisocyanate which has a hydrocarbon group with 5 or more carbon atoms in a side chain. In particular, the allophanate group-containing polyisocyanate is preferably obtained by reacting an alcoholic hydroxyl group-containing compound having 5 or more carbon atoms with an organic diisocyanate by using an organic carboxylic acid bismuth salt and an organic phosphite triester. Such a polyurethane resin composition can be suitably used as an adhesive for a base made of a resin having a low polarity such as a polyolefin film.