The present invention provides a semiconductor laser device of which reliability is enhanced. In the semiconductor laser device of the present invention, a semiconductor laser element 3 emitting laser light in a plane direction, a reflection mirror 4 reflecting the laser light in an upper direction and a light acceptance unit 5 detecting signal of incident laser light are disposed inside an insulative frame 2. A plurality of leads 8 extending in a horizontal direction are fixed in the end walls 2a, 2b opposed to each other in the longitudinal direction of the insulative frame 2. The insulative frame 2 is made of liquid crystal polymer.