Abstract: The present invention relates to an optical data link having a structure which is quite easy to manufacture at a low cost and realizes high optical accuracy, high mechanical accuracy, and high reliability. This optical data link comprises a light-receiving module for outputting an optical signal from an optical fiber transmission line as an electric signal, and a light-emitting module for transmitting the optical signal to the optical fiber transmission line. Each of these optical modules comprises a body portion including an electronic device; a head portion including a light-receiving device or light-emitting device; and a neck portion, processed into a predetermined form, for communicating the body portion and head portion to each other. The optical modules are mounted on an insulating substrate, and are at least partly accommodated in a housing, while being separated from each other by a predetermined distance.