To provide a block copolymer composition having a good balance in transparency and impact resistance, and particularly having an excellent impact resistance, by making a molded product of injection molding under high sear condition in such a manner as to hardly generate anisotropy. A block copolymer composed of a hard segment block comprising a block made mainly of a vinyl aromatic hydrocarbon and a soft segment block comprising a block made mainly of a conjugated diene, characterized by having a remarkably improved impact resistance without degrading transparency in respect of not only an extrusion-molded product and a blow-molded product but also an injection-molded product, by blending two kinds of block copolymers having a hard segment block of a specific structure.