A spectrophotometer having a light-receiving optical system that images light to be measured from a position for measurement and generates imaged light to be measured; a slit formation including a slit that causes the imaged light to be measured to pass and that generates light to be measured, which travels along a measurement optical path; a grating that diffracts the light to be measured, which travels along the measurement optical path, and generates diffracted light; a sensor that receives the diffracted light and outputs a signal representing a spectral spectrum; and an observation light source that is disposed on an optical path of zeroth light among the diffracted light and that emits observation light toward the grating at a time of observing the position for measurement.