PURPOSE: To reduce the size and cost of a titled input equipment by constituting a matrix circuit by utilizing the reverse current stopping effect of a receiving element which constitutes an insulating part.

CONSTITUTION: Light insulating elements (photocoupler) are used as insulating parts 1IS∼64IS for external input signals. Those light insulating elements are constituted by arranging light emitting elements 1T∼64T and photodetecting elements 1R∼64R in opposition. The light emitting elements 1T∼64T are connected to various switches S1∼S64 as signal generating sources each at one end, and also connected to a power source V1 each at the other end to constitute an external signal system. The photodetecting elements 1R∼64R are each connected to one of longitudinal lines Y1∼Y8 at one end (emitter terminal E), and connected to one of lateral lines X1∼X8 at the other end (collector terminal C) to constitute a matrix circuit which is part of an internal processing system.