PURPOSE: To unify a semiconductor element as a heating source and a cooling mechanism, and to cool the semiconductor element directly by installing the cooling mechanism such as a loop type heat pipe into an element forming substrate.

CONSTITUTION: A specified semiconductor element is formed to one part 11 on a substrate 10. A flow path 12 for circulating a heating medium along the surface direction of the substrate 10 is shaped into the substrate 10, and the flow path 12 is formed so as to pass just under the semiconductor element section 11. The heating medium is sealed into the flow path 12, and the flow path 12 forms one loop and is closed as a system. The flow path 12 constitutes a heat exchanger, the lower section of the semiconductor element section 11 functions as a heat-receiving section and regions except said lower section as a heat-dissipating section, and the circulating phase change of the heating medium is also generated. Heat is exchanged by a heat pipe.