A pressure detecting device includes: a resonator whose oscillation frequency varies depending on a pressure; a first oscillation circuit that oscillates the resonator and outputs a signal of a frequency corresponding to the pressure; an AT-cut quartz crystal resonator; a second oscillation circuit that oscillates the AT-cut quartz crystal resonator and outputs a reference clock signal; a measuring unit that measures the reference clock signal by the use of a reciprocal counting method; a temperature detecting unit that detects a temperature of the resonator; and a storage unit that stores coefficients of a first approximating polynomial for calculating a first correction value used to compensate for a frequency-temperature characteristic of the measuring unit, wherein the frequency-temperature characteristic of the value measured by the measuring unit includes a frequency-temperature characteristic of the AT-cut quartz crystal resonator and a frequency-temperature characteristic of the resonator.