PURPOSE: To provide the titled resin compsn. having good moldability, transparency, strength flexibility, resistance to heat, weather and cold, etc., by using, as a base resin, a blend obtd. by blending a specified polypropylene polymer with a specified block copolymer which is used as a base.

CONSTITUTION: A block copolymer wherein both terminal blocks are composed of an arom. vinyl compd. polymer and the intermediate block is composed of a conjugated diene polymer, is prepd. As said terminal block, those having a number-average MW of 5,000W125,000 are suitable. For example, polystyrene is preferred, and accounts for 10W40wt% of the block copolymer, and not more than 10% of the block is hydrogenated. As the intermediate block, polybutadiene having a number-average MW of 10,000W300,000 is preferred and not less than 10% thereof is hydrogenated. The titled compsn. consists of 60W98wt% said block copolymer and 40W2wt% isotactic polypropylene or copolymr mainly composed of the same.