A refrigerant jacket includes a refrigerant cooling member, a cover member and a strength member. The cooling member is constructed of aluminum or aluminum alloy that thermally contacts a heat emitting electrical part, and has a groove portion. A refrigerant tube of a refrigerant circuit fits into the groove portion. The cover member covers the refrigerant cooling member in a state where the refrigerant tube has been fitted into the groove portion. The strength member is higher in strength than the cooling member, and is fixed to the cooling member. The cover member has a cover-side through hole opposing the strength member. The strength member has a cover member fixing screw hole opposing the cover-side through hole. The cover member is fixed to the strength member by a cover member fixing screw that passes through the cover-side through hole and screws into threads of the cover member fixing screw hole.