A spectral characteristic measurement method for measuring spectral characteristics of measured light with higher accuracy is provided. The spectral characteristic measurement method includes causing an optical measurement instrument having detection sensitivity in a first wavelength range to receive light in a second wavelength range which is a part of the first wavelength range, obtaining characteristic information indicating a stray light component from a portion of a first spectrum detected by the optical measurement instrument, that corresponds to a range other than the second wavelength range, and obtaining a pattern indicating a stray light component generated in the optical measurement instrument by subjecting the characteristic information to extrapolation processing as far as the second wavelength range in the first wavelength range.