An optical detection unit includes a light emitting portion 150 that emits light toward a target object, a light receiving portion 140 that receives light from the target object, and a light blocking member 70 that blocks light from being incident to at least the light receiving portion 140. The light blocking member 70 includes a light blocking wall 100 that is formed by performing sheet metal processing on a metal, and is provided between the light emitting portion 150 and the light receiving portion 140 so as to block light from the light emitting portion 150 from being incident to the light receiving portion 140. The light blocking wall 100 is formed of a first metal surface 71 of the light blocking member 70.