device is small that is the resonant length of the high output ld required for high output operation can be sufficiently guaranteed and at the same time the overall length of the semiconductor laser device can be considerably reduced when compared to that of conventional semiconductor laser devices accordingly the number of devices that can be produced per unit wafer is increased moreover since sufficient yield of devices can be achieved without the need of reducing the width w 1 of the unit ld deterioration of process margins which is a problem of conventional semiconductor laser devices can be prevented fig3 is a plan view of a multi wavelength semiconductor laser device according another embodiment of the present invention the multi wavelength semiconductor laser device shown in fig3 is identical to that shown in fig2 except that a ridge structure 131 a of a high output ld has parts overlapped by bent parts a ridge structure 131 b of a low output ld is rectilinear but the ridge structure 131 a has two or more bent parts accordingly the semiconductor laser device can reduce the operation current of the low output ld while ensuring a sufficient resonant length of the high output ld in addition since the semiconductor laser device can reduce the entire length l 2 of the device without reducing the width w 2 of the device it can prevent deterioration of.