To provide a heat sink structure which can sufficiently dissipate heat released from heat release devices, one is of low critical temperature and the other is of high critical temperature, enhanced in assembly, formed through an inexpensive press die, and enhance the heat release devices in degree of freedom of layout.

Two heat sinks 14 and 15 are structurally assembled integrally, and heat is restrained from being transferred from the heat sink 14 to the heat sink 15 and vice versa by thermal conduction. The heat sinks 14 and 15 are set different from each other in heat dissipation area, a heat release device 3 of low critical temperature is attached to the heat sink 14 larger in heat dissipation area, and a heat release device 4 of high critical temperature is attached to the heat sink 15 smaller in heat dissipating area.