The present invention relates to wavelength tunable DBR semiconductor laser devices in which light waves generated from a plurality of laser portions (or laser channels) are combined. This type of semiconductor laser device requires that the laser channels together cover an entire desired wavelength range, allowing the oscillation wavelength to be continuously varied over this range. However, to accomplish this, it is necessary to employ highly accurate crystal growth and process techniques. Furthermore, the length of the gain region must be reduced to increase the range over which the oscillation wavelength can be continuously varied, making it difficult to achieve laser oscillation.Two laser channels operate in combination, and a combiner combines the light waves emitted from these laser portions (or laser channels) so as to cover one entire wavelength range. Specifically, an inter-grating element distance Lgrt1 of the first laser portion is set larger or smaller than an inter-grating element distance Lgrt2 of the second laser portion by one half of the grating pitch. This allows these laser portions to exhibit different mode-hopping DBR current values appropriately adjusted against each other and thereby together cover a desired wavelength range.