A light-receiving unit which is simplified by dispensing with a case or a lens and thus improved in manufacturing efficiency and lowered in manufacturing cost is disclosed. The light-receiving unit comprises: a lens for converging light, which is emitted from a light source and then reflected from a contacting object, in which the light carries an image formed on the contacting object; a printed circuit board having a light hole for allowing the light converged by the lens to be passed therethrough; and a molding package made by molding lead frames electrically connected to the printed circuit board and an optical sensor bonded to the lead frames with transparent resin, which is adapted to detect the image carried in the converged light.