An optical characteristic measurement device includes a photodetector and a processor. The photodetector has a detection surface greater than a light incident surface receiving light from a spectrometer. The processor is configured to obtain a measurement spectrum detected in a first detection area corresponding to the light incident surface and a signal intensity detected in a second detection area different from the light incident surface, correct a pattern prepared in advance and exhibiting a noise characteristic of the photodetector based on the signal intensity to calculate a first correction spectrum, subtract a correction value calculated based on the signal intensity from each component value of the measurement spectrum to calculate a second correction spectrum, and subtract each component value of the first correction spectrum from a corresponding component value of the second correction spectrum to calculate an output spectrum.