The present invention provides a pressure detecting circuit, which is electrically connected to a coil to receive an induced electromotive force from the coil, including a movement detecting unit electrically connected to the coil to receive the induced electromotive force from the coil and find a distance of the movement of the magnetic device according to the induced electromotive force; and a converting unit electrically connected to the movement detecting unit to generate the voltage signal to indicate the distance. In addition, the present invention further provides a pressure gauge incorporated with the pressure detecting circuit.