A three-dimensional measurement device , comprising: a predetermined optical system configured to split a predetermined incident light into two lights, to radiate one of the two lights as a measurement light to a measurement object (W) and the other of the two lights as a reference light to a reference surface , and to recombine the two lights to a combined light and emit the combined light; a first irradiator configured to emit a first light that includes a polarized light of a first wavelength (λ 1 ) and enters a first input-output element of the predetermined optical system ; a second irradiator configured to emit a second light that includes a polarized light of a second wavelength (λ 2 ), which is different from the first wavelength (λ 1 ), and enters a second input-output element of the predetermined optical system ; a first imaging unit configured to take an image of an output light with regard to the first light that is emitted from the second input-output element when the first light enters the first input-output element ; a second imaging unit configured to take an image of an output light with regard to the second light that is emitted from the first input-output element when the second light enters the second input-output element ; and an image processor configured to perform three-dimensional measurement of the measurement object (W), based on interference fringe images taken by the first imaging unit and the second imaging unit, characterized in that the predetermined optical system comprises a polarizing beam splitter , the first input-output element is a first surface of the polarizing beam splitter , and the second input-output element is a second surface of the polarizing beam splitter , which is different from the first surface . a predetermined optical system configured to split a predetermined incident light into two lights, to radiate one of the two lights as a measurement light to a measurement object (W) and the other of the two lights as a reference light to a reference surface , and to recombine the two lights to a combined light and emit the combined light; a first irradiator configured to emit a first light that includes a polarized light of a first wavelength (λ 1 ) and enters a first input-output element of the predetermined optical system ; a second irradiator configured to emit a second light that includes a polarized light of a second wavelength (λ 2 ), which is different from the first wavelength (λ 1 ), and enters a second input-output element of the predetermined optical system ; a first imaging unit configured to take an image of an output light with regard to the first light that is emitted from the second input-output element when the first light enters the first input-output element ; a second imaging unit configured to take an image of an output light with regard to the second light that is emitted from the first input-output element when the second light enters the second input-output element ; and an image processor configured to perform three-dimensional measurement of the measurement object (W), based on interference fringe images taken by the first imaging unit and the second imaging unit, characterized in that the predetermined optical system comprises a polarizing beam splitter , the first input-output element is a first surface of the polarizing beam splitter , and the second input-output element is a second surface of the polarizing beam splitter , which is different from the first surface . <EOS>