Patent ID: 8023832

Claim:
A light receiving circuit comprising: a light inputting circuit converting a one-system optical signal to be outputted from an optical transmission path to an electrical signal and inverting a potential of the electrical signal each time the optical signal is detected; and a buffer circuit amplifying the electrical signal converted by the light inputting circuit and outputting the electrical signal, wherein the light inputting circuit includes: a light receiving element detecting the optical signal from the optical transmission path; a first switching circuit being connected to a second signal line which transmits the electrical signal to the buffer circuit, a first signal line to which the same potential as a potential of the second signal line is given, and a power supply line from a ground; and a second switching circuit being connected to the second signal line, the first signal line, and a power supply line from an operational power supply, wherein the first switching circuit makes the second signal line short-circuit to the power supply line from the ground in the case where the potential of the first signal line is equal to a potential of the power supply line from the operational power supply when the light receiving element detects the optical signal, and the second switching circuit makes the second signal line short-circuit to the power supply line from the operational power supply in the case where the potential of the first signal line is equal to a potential of the power supply line from the ground when the light receiving element detects the optical signal.