A semiconductor laser light source includes a semiconductor laser (1), and a sub-mount (2). The sub-mount (2) includes a sub-mount substrate (20), an Au layer (22) placed above the sub-mount substrate (20), a barrier layer (23) which is placed on the Au layer (22) and has a barrier portion (23b) at least in a portion of its outer peripheral portion which is other than a portion corresponding to a side of an output end of the semiconductor laser (1), and a solder layer (25) placed on the barrier layer in an area surrounded by the barrier portion (23b), wherein the semiconductor laser (1) is bonded to the sub-mount (2) through the solder layer (25), in a state where the semiconductor laser (1) is spaced apart by a predetermined interval from an inner surface of the barrier portion (23b), and further, the output end protrudes, in a direction of output of the laser light, from an end of the solder layer (25) which corresponds to the side of the output end of the semiconductor laser (1).