In an optical module, a member has a hole and a mounting surface in which the hole is open and electric wiring is formed. A recess is formed in the mounting surface. The electric wiring is formed in the recess and is continuously extended to an outside the recess. The electric wiring is provided with a connecting portion on a bottom surface of the recess. An optical transmission line is inserted into the hole and its optical input or optical output end is faced to the optical semiconductor device so as to be optically coupled to the optical transmission line. The semiconductor device is mounted on the mounting surface and electrically connected to the connecting portion. The gap between the optical semiconductor device and the opening end face of the optical transmission line is filled with an adhesive.