To provide a capacitance type pressure sensor for absolute pressure measurement having higher accuracy or reliability, and an evaluation method for evaluating the degree of vacuum in a vacuum chamber thereof.

In this capacitance type pressure sensor, a movable electrode 6 displaced by a diaphragm 3 pressure and a fixed electrode 5 provided oppositely to the movable electrode 6 are provided in the vacuum chamber 4, and a capacitance between the movable electrode 6 and the fixed electrode 5 is measured, to thereby measure the pressure in the diaphragm. The pressure sensor is provided in the vacuum chamber 4 with a pair of terminals 7c, 7d for measuring the degree of vacuum to be extracted to the outside. A high voltage is applied to one of the terminals 7c, 7d for measuring the degree of vacuum, and a discharge current is measured from the other electrode, to thereby measure the degree of vacuum in the vacuum chamber 4 and evaluate the degree of vacuum.