PURPOSE: To make an adapter smaller and less expensive by making up a subscriber terminating set and a circuit in a terminal adapter, into a 3-dimensional IC and incorporating these circuits to a socket where an optical fiber is loaded.

CONSTITUTION: An optical fiber 2 is connected through an optical socket 1 to a terminal adapter 3, and positioned on the light receiving surface of a photoelectric converter (O/E) of a three-dimensional IC 5. In addition, a signal directly bonded from a pad on the IC 5 or bonded on to a substrate is outputted from an electric output connector 4 to each terminal. The three-dimensional IC 5 consists of an Si layer for the lower layer and a compound semiconductor for the upper layer, the top layer is positioned to the top of the optical fiber 2, and the O/E is formed. Thus, the small and socket-type picture terminal adapter can be composed.