To provide a resin composition which is excellent in heat resistance, thermal conductivity, insulation, fluidity at molding, and device abrasion at molding, whose molded article is hardly broken, and which is inexpensive.

The resin composition includes a crystalline thermoplastic resin (A), an amorphous α-olefinic copolymer (B), and a filler having a thermal conductivity of 10 to 100 W/m-K (C). The amorphous α-olefinic copolymer (B) contains monomer units originated from at least two olefins selected from the group consisting of ethylene, propylene and 4-20C α-olefins, and has a molecular weight distribution (Mw/Mn) of 1 to 4, wherein the content of the crystalline thermoplastic resin (A) is 0.3 to 40 vol%; the content of the amorphous α-olefinic copolymer (B) is 15 to 80 vol%; and the content of the filler (C) is 20 to 70 vol%.