A semiconductor laser device comprises a semiconductor laser element, a photodetector to receive laser light emitted from the semiconductor laser element, and a stem on which the semiconductor laser element and the photodetector are mounted. The semiconductor laser element is disposed on a side to a stem front face between the stem front face and a farthest portion of the photodetector farthest away from the stem front face of the stem on which the semiconductor laser element and the photodetector are mounted. The photodetector has a light receiving face for receiving the laser light and a reflective film formed thereon in which part of the laser light is transmitted and the rest is reflected, the light receiving face being formed on a side facing the semiconductor laser element.