A semiconductor laser device including an edge-emitting type laser chip having at least three emitting points in one light emitting edge, a sub-mount mounted with the laser chip, and a heat sink bonded to the sub-mount through a solder layer. When R designates a linear expansion coefficient ratio of the heat sink to the sub-mount and D designates a distance between light emitting points at opposite ends in the light emitting edge of the laser chip, materials of the sub-mount and the heat sink and the distance D are set to satisfy the following relation: D.ltoreq.5.48.times.R.sup.-2.13 A difference between stress acting on one laser element and another in the laser chip due to shrinkage of the heat sink when melted solder is cooled down is reduced so that a difference in light output characteristics between one light emitting point and another can be reduced.