PURPOSE: To obtain the composition useful for industrial materials, etc., having excellent rigidity, heat resistance, impact resistance and water resistance by blending a styrenic polymer having syndiotactic structure, a thermoplastic resin containing a reactive polar group, a specific rubber-like elastic material and a compatibilizing agent.

CONSTITUTION: This resin composition is obtained by blending (A) 1-95wt.% of a styrenic polymer having syndiotactic structure with (B) 1-95wt.% of a thermoplastic resin containing a reactive polar group, (C) 1-50wt.% of a rubber- like elastic material having affinity for the component A (hydrogenated styrene- butadiene-styrene block copolymer) and (D) 0.1-10wt.% of a compatibilizing agent having compatibility with the component A and a polar group to be reacted with the component B. The resin composition having excellent toughness, compatibility, acid.alkali resistance, etc., is obtained.