A circuit device includes a comparator and a flag signal generation circuit. The comparator includes a first voltage-time conversion circuit to which at least a first input signal is input and which outputs a first time information signal, a second voltage-time conversion circuit to which at least a second input signal is input and which outputs a second time information signal, and a determination circuit that determines magnitude relation of the first input signal and the second input signal, based on the first time information signal and the second time information signal. The flag signal generation circuit generates a flag signal indicating that a voltage difference between the first input signal and the second input signal is a predetermined voltage or less, based on the first time information signal and the second time information signal.