Hitherto, there is known a pressure change measuring apparatus for detecting a minute pressure change, which has structure including an inner chamber (pressure chamber), a differential pressure gauge (diaphragm or the like) configured to detect a differential pressure between a pressure of the inner chamber (pressure chamber) and a pressure to be measured, and a pressure through hole configured to allow flowing of a pressure transmission medium for transmitting pressure to be measured into and out of the inner chamber (pressure chamber) (see, for example, PTLs 1 to 3). The pressure through hole has extremely small structure, and restricts the flowing of the pressure transmission medium into the inner chamber (pressure chamber). Further, the pressure within the inner chamber (pressure chamber) changes depending on an amount of the pressure transmission medium flowing into and out of the inner chamber (pressure chamber), and hence the pressure within the inner chamber (pressure chamber) follows the change in the pressure to be measured with a delay. Therefore, the differential pressure between the pressure of the inner chamber (pressure chamber) and the pressure to be measured is detected, to thereby be able to extract and detect only the pressure change to be measured. Such a pressure change measuring apparatus has a feature that a minute pressure change can be detected with high sensitivity irrespective of a ratio of the pressure change to the pressure (absolute pressure) to be measured.