A semiconductor laser apparatus is provided which comprises a semiconductor laser device for emitting laser light and a base having a major surface and a circumferential side surface. The circumferential side surface has an upper surface and a lower surface. The semiconductor laser device is mounted on the major surface of the base. At least one of the upper and lower surfaces of the circumferential side surface is tilted from a direction perpendicular to the major surface so that a height in a vertical direction of the semiconductor laser apparatus is reduced or minimized.