An infrared laser light source spreader has a first biconvex lens, a biconcave lens, a convex-concave lens, and a second biconvex lens. Light from an infrared laser light source is emitted incident to the first biconvex lens, spreads and exits to be incident on the biconcave lens, is further spread and inverted by the biconcave lens, exits to be incident on the convex-concave lens, which collimates the light, and becomes incident on the second biconvex lens, which spreads the light further.