An optical module comprises an optical connector at the receiver side and an optical connector at the transmitter side, and hybrid IC for the receiver side and the transmitter side are mounted on a lead frame. The lead frame comprises a projecting part projecting outside from a part where each semiconductor chip is mounted. Nearby the connection part between the optical connector and the hybrid IC, the projecting part is connected to a ground pattern on a surface of the hybrid IC by a bonding wire. The wire is placed at this location, so that the effect of noise caused by an atmospheric electric wave, or GND/power lines can be reduced.