A differential amplifier circuit amplifies a difference between an input analog signal and a ramp signal which changes over time and outputs a difference signal. An amplifying element amplifies the difference signal and outputs the same as an amplified signal. A time measuring unit measures a length of a conversion period until a level of the analog signal substantially coincides with a level of the ramp signal on the basis of a level of the amplified signal and outputs the same as a digital signal obtained by converting the analog signal. One end of a capacitor is connected to one of an input terminal and a predetermined connection terminal of the amplifying element. A switch connects the other end of the capacitor to the other of the input terminal or the predetermined connection terminal in the conversion period, and disconnects the other end outside the conversion period.