To increase the breakdown voltage of an element, while sensitivity of the element is increased and the area of the element is maintained small.

This high breakdown voltage planar light-receiving element is provided with a P-type diffusion region 3, formed on the main surface of an N-type silicon substrate 1, an anode electrode 5 having an end portion, which does not reach a part above a P-N junction for regulating the P-type diffusion region 3, and a transmissive low resistivity part 11 which is formed in the vicinity of the part above the P-N junction via a silicon oxide film 4. An overlay length L1 from the P-N junction to the end portion of the low resistivity part 11 is at least 10 μm and at most 100 μm. This bidirectional photothyristor element has the above high breakdown voltage planar structure.