A comparator circuit includes a first comparator configured to compare a voltage based on an input voltage with a first reference voltage, a charge/discharge portion configured to switch between charging and discharging of a capacitor based on an output of the first comparator, a second comparator configured to compare a voltage of the capacitor with a second reference voltage, and a control portion. The control portion is configured to, in a case where the voltage of the capacitor is larger than a predetermined value when the charge/discharge portion performs switching from the charging of the capacitor to the discharging thereof, supply a predetermined voltage instead of the voltage based on the input voltage to the first comparator until the voltage of the capacitor becomes smaller than the predetermined value so that the discharging of the capacitor is maintained by the charge/discharge portion.