A thermoplastic resin composition comprising (a) 50-99% by weight of a polyarylenesulfide resin and (b) 50-1% by weight of a norbornene-type resin as essential components is disclosed. This resin composition possesses excellent stiffness properties and high heat resistance, and exhibits only small anisotropic properties and superior moldability during the molding operation, and is useful for molding various electronic parts, household electric or electronic parts and articles. Those having a Vicut softening point of 200.degree. C. or higher are especially useful for sealing electronic parts or photo-semiconductors.