Resin compositions of the invention contain an olefin polymer wax having higher heat resistance than achieved heretofore, high compatibility with resins and excellent mold-releasing properties.A resin composition (X) of the invention is obtained by blending a resin (A) having a melting point Tm of not less than 200° C. and an olefin polymer wax component (B), the olefin polymer wax component (B) including a cyclic olefin polymer wax (B-1) having structural units (a) and (b) described below, the cyclic olefin polymer wax (B-1) containing the structural units (b) at 0.05 to 50 mol % based on all the structural units in the polymer; (a) units derived from ethylene (b) units derived from a cyclic olefin.