PURPOSE: To obtain an easily moldable polyurethane elastomer having excellent heat-resistance and mechanical properties, producible at a low cost and suitable as synthetic leather, etc., by curing a specific prepolymer with a polyol.

CONSTITUTION: This elastomer is produced by curing (A) a prepolymer composed of (i) a polyisocyanate containing preferably 6-100wt.% of p-xylylene diisocyanate and (ii) a polymer polyol with (B) a polyol, preferably 1,4- butanediol. The ratio of the number of the molecules of the component B to the number of isocyanate groups of the component A is preferably 0.1-3.0 and the ratio of the isocyanate group of the component (i) to the OH group of the component (ii) is preferably 1.5-15.