To provide a position measuring apparatus that suppresses a measuring error due to a quantization error generated when outputs of an interferometer and a wavelength compensator are converted into digital signals.

The position measuring apparatus includes an interferometer for measuring a position of a moving body, a wavelength compensator for compensating for a wavelength change in measurement light of the interferometer due to a state of gas in an optical path of the measurement light, and a controller for output of a position measurement value corresponding to an output of the wavelength compensator. The controller includes an analog-digital converter for converting outputs of the interferometer and the wavelength waveform compensator into digital signals and the resolution generated when the output of the wavelength compensator is converted into a digital signal is set to be higher than that generated when the output of the interferometer is converted into a digital signal.

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