In the optical fiber collimator according to the invention, a transparent block having a refractive index that is substantially the same as the refractive indices of the lens and optical fiber is disposed between the lens and ferrule so that the block contacts the lens, ferrule, and optical fiber. The thickness of the block in the direction of beam transmission is set to be the same as the distance to the focal point from the end surface of the lens that is determined by the diameter and refractive index of the lens and the refractive index of the block.