A comparator circuit includes a differential input circuit, a load circuit, a first current source, a first bias voltage supplying circuit, a third connection circuit, and a fourth connection circuit. The differential input circuit includes a first transistor to which a first input signal is supplied and a second transistor to which a second input signal is supplied. The load circuit includes a third transistor connected to the first transistor through a first connection circuit and a fourth transistor connected to the second transistor through a second connection circuit, gates of the third and fourth transistors being connected to the first connection circuit through a third capacitor. The first bias voltage supplying circuit supplies a first bias voltage to the gates of the third and fourth transistors and the third capacitor.