To receive a light signal even if background light is enhanced, while preventing the deterioration of S/N of a received signal, in a device for receiving the light signal through a photodiode.

In this light signal receiving device, a resistance element is provided between the anode of the photodiode 34 and the ground, and a backward bias voltage is applied to the photodiode 34 through the resistance element, and thereby a current corresponding to incident light from the vehicle periphery is made to flow in the photodiode 34, and an alternating-current signal component in the current is extracted through a capacitor 38, thereby acquires a received signal of the light signal wherein the background light is removed from the incident light. The resistance element connected in series to the photodiode 34 is constituted of FET 36 capable of controlling a resistance value, and the resistance value is controlled so that the anode side potential (direct-current component) of the photodiode 34 acquired through a low-pass filter comprising a resistance 42 and a capacitor 44 becomes a constant standard potential.