Pressure-detecting device

The invention discloses a pressure-detecting device (10) which comprises a pressure-detecting element (21 (21a, 21b, 21c)) and a processing circuit (30). Upon being subjected to pressure (P), the pressure-detecting element (21) outputs a detection signal (Qi) corresponding to said pressure (P), and the processing circuit (30) processes the detection signal (Qi) outputted by the pressure-detecting element (21) and outputs the result. The processing circuit (30) contains the following: a voltage-transformation circuit (35) whereby a power-supply voltage (Vdd) provided by an external power supply is subjected to voltage transformation only, yielding a first reference voltage (Vr1) having a prescribed voltage value; an integrating circuit (31) that converts the detection signal (Qi) to a voltage waveform by integrating said detection signal (Qi) using the aforementioned first reference voltage (Vr1) as an operating reference; and one or more amplifier circuits (32,...) that, using a second reference voltage (Vr2)