PURPOSE: To prevent heat of a semiconductor laser drive circuit from conducting thermally to a semiconductor laser chip with simple constitution by laminating incorporatedly a member having a poor thermal conductivity between members having a good thermal conductivity and adopting the structure separating thermally the semiconductor laser drive circuit and a semiconductor laser chip.

CONSTITUTION: For example, copper is used as a material for flat plates 1, 5 and a frame member 2, and for example, beryllia is used for a board 3 mounting a semiconductor laser drive circuit and for example, forsterite is used for the frame member 4 to isolate thermally the board 3 and the flat plate 5. The members are laminated incorporatedly to form an optical communication equipment 6. The semiconductor laser driving circuit, e.g., an IC8 is mounted on the board 3. Thus, the heat from the IC8 is conducted to the board 3 into the member 2 and the flat plate 1, where heat is dissipated and the thermal conduction to the flat plate 5 is limited by the member 4. Since the forsterite has nearly equal expansion coefficient with that of copper, the deterioration in the air-tightness and environmental resistance is prevented. For example, silicon is used for the material of a heat sink 10 to dissipate the self-heat of the chip 9.