To obtain a molded article having no pin holes and excellent in surface characteristics and mold-release characteristics by rotational molding using a powder composition having a particle size of 1,000 μm or more with a low production cost.

When polypropylene is added to a styrene-based block copolymer to impart hardness to the copolymer, a highly flowable polypropylene which does not obstruct rotational molding is used. Further, an ethylene-ethylene/butylene-ethylene block copolymer is added to improve compatibility between the styrene-based block copolymer and polypropylene.