PURPOSE: To position and fix an optical semiconductor device with an accuracy of a submicron order.

CONSTITUTION: An Au layer 3 and an Sn layer 4 are formed into layers on a barrier layer 8 which is formed on an optical semiconductor device mounting part 2 of an optical circuit board 1. An Au layer 5 having a predetermined thickness is formed on the Au layer 3 and the Sn layer 4 as an uppermost layer to form the joint part of the optical semiconductor device mounting part 2. The electrode plane 10 of the optical semiconductor device 9 is brought into contact with the Au layer 5 which is the uppermost layer of the joint part and pressed and then heated to bond the optical semiconductor device 9 to the optical semiconductor device mounting part 2 of the optical circuit board 1.