Abstract: A circuit device is constituted by including: a detection circuit configured to include a first A/D conversion circuit that A/D converts a signal output from a sensor element to output a first digital signal and generate a detection signal in accordance with the first digital signal; a pseudo-detection circuit configured to include a second A/D conversion circuit that A/D converts a signal output from the sensor element to output a second digital signal and generate a pseudo-detection signal in accordance with the second digital signal; and a failure detection circuit configured to detect a failure of the detection circuit in accordance with a comparison result produced by comparing a value of the detection signal and a value of the pseudo-detection signal.