A transfer switch is disposed between an output terminal of a photoelectric converter and an input terminal of an amplifier. The input terminal of the amplifier being connected to a reset switch. After accumulation of a light signal of the photoelectric converter, a reference signal held at the input terminal of the amplifier is read from the output terminal of the amplifier, the transfer switch is turned on to transfer light signal charge of the photoelectric converter to the input terminal of the amplifier, after the transfer switch is turned off, a light signal held at the input terminal of the amplifier is read from the output terminal of the amplifier as a light signal, the transfer switch and the reset switch are turned on to reset the output terminal of the photoelectric converter and the input terminal of the amplifier, and after the reset switch is turned off, the transfer switch is turned off.