A spectrophotometer and spectrophotometry method, using a precision drive at a photodiode array which precisely moves the photodiode array by a distance equal to the physical interval between the photodiodes of the photodiode array so that the spectrophotometer and spectrophotometry method primarily measures light intensities of incident light by the photodiode array, and when precisely moves the photodiode array using the drive by the distance equal to the physical interval between photodiodes of the photodiode array, measures the light intensities of the incident light at desired positions corresponding to the intervals.