To provide a technology of solving problems of being apt to upsize a heat sink device, a thermoelectric conversion member, and a heating element fixing member to ensure a wiring space and cause a deteriorated heat dissipating efficiency; and achieving low power consumption/and space saving.

A heating element 9 is clamped between an LD holder 8 and an LD retainer 10 made of a material with excellent heat conductivity, and the folded part of the LD holder 8 is closely adhered to a thermoconductive plate 12 from the outside of a wiring board 11. The thermoconductive plate 12 is closely in contact with a thermoelectric conversion member 13, and the heat generating face of the thermoelectric conversion member 13 is closely adhered to a heat sink 14. The heat from the heating element 9 flows through a path directly reaching the thermoconductive plate 12 from the LD holder 8, and a path reaching the thermoconductive plate 12 via the LD holder 8 from the LD retainer 10. The heat from the thermoconductive plate 12 flows to the thermoelectric conversion member 13 and the heat sink 14.

COPYRIGHT: (C)2007,JPO&INPIT