Second and third p-side pad electrodes are formed on an insulating film of a blue-violet semiconductor laser device on both sides of a first p-side pad electrode. The second p-side pad electrode and the third p-side pad electrode are formed separately from each other. Solder films are formed on the upper surfaces of the second and third p-side pad electrodes respectively. A fourth p-side pad electrode of a red semiconductor laser device is bonded onto the second p-side pad electrode with the corresponding solder film sandwiched therebetween. A fifth p-side pad electrode of an infrared semiconductor laser device is bonded onto the third p-side pad electrode with the corresponding solder film sandwiched therebetween. The second and third p-side pad electrodes are formed separately from each other, so that the fourth and fifth p-side pad electrodes are electrically isolated from each other.