Abstract: A photoelectronic switch circuit of a pulse-modulated light system adapted to emit pulse light and conduct detecting operation by detecting only the photo-reception signal synchronized with the pulse light, and it comprises a counter control circuit for resetting or presetting the output signal from a counter if the number of pulse light successively received is less than a predetermined number to eliminate the effect, if any, of external disturbance light and facilitates to attain the integrated circuit by reducing the number of parts for the circuit constituting portion.