To provide a polybutylene terephthalate resin composition that excels in the anti-heat shock property, flame retardation and hydrolysis resistance. A polybutylene terephthalate resin composition is prepared by combining a halogenated benzylacrylate compound, an antimony oxide compound and a carbodiimide compound with the polybutylene terephthalate resin. The content of the carbodiimide compound may be an amount that makes the amount of the carbodiimide functional group to be at least 0.3 equivalents and no more than 5.0 equivalents, when the terminal carboxyl equivalent of the polybutylene terephthalate is set as 1.