A circuit device includes a first terminal, a second terminal, a receiving circuit configured to receive the differential signals via the first terminal and the second terminal, a first signal line connecting a first input terminal of the receiving circuit and the first terminal, a second signal line connecting a second input terminal of the receiving circuit and the second terminal, a first capacitor circuit having one end connected to the first signal line, a second capacitor circuit having one end connected to the second signal line, and a detection circuit configured to detect a duty cycle of an output signal that is output from the receiving circuit.