According to one embodiment, a delta/sigma modulator includes a first multiplier based on a reference capacitor having capacitance CR and a first variable capacitor having capacitance CS1 according to a distance between electrodes thereof, the first multiplier being defined by a first multiplier factor given by CR/CS1 and being supplied with a reference voltage, a second multiplier based on a second variable capacitor having capacitance CS2 and a third variable capacitor having capacitance CS3, the second multiplier being defined by a second multiplier factor given by CS3/CS2 and being provided in a feedback path, and an adder configured to add an output of the first multiplier and an output of the second multiplier, wherein CS1, CS2 and CS3 are the same.