Spectrometry device and spectrometry method

A spectrometry device according to the present invention is provided with: a light source 101 that causes p-polarized light, which is linearly polarized light having an electric field vibration direction parallel to the incidence surface, to be incident on the surface of an object of measurement at Brewster's angle; an introduction optical system 103 for introducing measurement light emitted from the object of measurement struck by the p-polarized light into a phase shifter 105 and dividing the same into two measurement light beams; an interference light optical system 106 for forming interference light from the two measurement light beams; an interference light detection unit 107 for detecting the intensity of the interference light; a processing unit 201 for creating an interferogram of the measurement light on the basis of the intensity variation of the interference light obtained through the driving of the phase shifter 105; and a calculation unit 202 for obtaining a measurement light spectrum by applying the Fourier transform to the measurement light interferogram.