A detection device includes a driving circuit which drives a physical quantity transducer, a detection circuit which detects a desired signal, a power-supply terminal into which a power-supply voltage is input, a regulator circuit which performs a voltage adjustment of stepping down the power-supply voltage from the power-supply terminal, and supplies a regulated power-supply voltage obtained by the voltage adjustment to the driving circuit and the detection circuit as an operating power-supply voltage, and a buffer circuit which is supplied with the power-supply voltage, receives a drive signal from the driving circuit, and outputs an amplified drive signal in which an amplitude of the drive signal increases to the physical quantity transducer.