An object is to obtain a module in which an optical fiber can be inserted after a ferrule has been mounted on a circuit board. There is provided an optical module (100) in which at least a ferrule (33) and an electric component (57) are mounted on a circuit board (35) on which external electrodes (63) have been mounted; a fiber through-hole is formed in the ferrule (33) in a position in which the optoelectric conversion device (31) is mounted on one end surface and that corresponds to an active layer of an optoelectric conversion device (31); and the optoelectric conversion device (31) of the ferrule (33) is electrically connected to the electric component (57). In the ferrule (33), an opening in the one end face of the fiber through-hole that faces the optoelectric conversion device (31) is blocked by a transparent substance (61), and a portion that excludes the fiber through-hole at the other end surface is are monolithically covered with a molding resin (55).