The present invention provides a polybutylene terephthalate resin composition which satisfies both performances such as high durability in an environment of heating and cooling cycle, and adhesion property to silicone rubber. Specifically, provided is a polybutylene terephthalate resin composition, exhibiting an excellent adhesion property to silicone rubber, containing: (A) 100 parts by weight of polybutylene terephthalate resin; (B) 5 to 30 parts by weight of a core-shell type polymer having a mean particle diameter of 2 μm or larger, in which a core layer is structured by an acrylic-based rubber, and (C) 20 to 100 parts by weight of glass fiber.