PURPOSE: To provide a capacitance type pressure sensor of high accuracy whose output voltage is proportional to applied pressure.

CONSTITUTION: An oscillation circuit 1 for oscillating an output signal of a frequency f0, a divider 10 for making 1/n (n: even number) of the frequency f0 of the output signal from the oscillation circuit 1 connected thereto, a switched capacitor circuit 11 connected thereto, a sample hold circuit 12 connected thereto, and a decoder 13 for producing a timing pulse on the basis of output from the divider 10 and giving it to the sample hold circuit 12 are provided. The switched capacitor circuit 11 has an operation amplifier 4, a reference capacitor 8 connected between the inverse input terminal of the operation amplifier 4 and the oscillation circuit 1, a pressure sensitive capacitor 5 connected between the inverse input terminal and the output terminal of the operation amplifier 4, and an analog switch 7 connected thereto in parallel and coupled to the divider 10.