PURPOSE: To provide an optically coupled device to realize the simplification of wiring and promote the miniaturization of equipment and information equipment using this.

CONSTITUTION: A data binary digit string for identification is stored in a first storing means 6 and a data binary digit string for control to control the counting of a counting means 11 is stored in a second storing means 7. A discriminating means 5 discriminates whether or not the data binary digit string sent from an external controller 14 through a signal transmitting line 2 is coincident with the data binary digit string for identification stored in the first storing means 6, the coincidence of the data binary digit string is discriminated, and then, a drive circuit 8 drives a light emitting element 9 and a light receiving element 10 and the counter means 11 counts a clock signal from the external controller 14 through a clock signal transmitting line 1. When the counted value becomes the one decided by the contents of the data binary digit string for control stored at the second storing means 7, the detected condition of the light receiving element 10 is outputted to an external control circuit 14 by an output control circuit 12. Then, the output of plural optically coupled devices can be transmitted to the external controller with two lines.