Spectrophotometer

A spectrophotometer including a light source for irradiating a sample with measurement light, a photodetector detecting light resulting from the sample being irradiated with the measurement light, a dispersing element located on an optical path between the light source and the sample or between the sample and the photodetector, and a processor dealing with a signal produced by the photodetector, comprising:

• a memory section used for storing a threshold value previously determined on a basis of an upper limit of a signal level that can be processed by the processor;
• a signal acquirer detecting, with the light source turned on, a value of either a detection signal produced by the photodetector or a signal fed to the processor at a wavelength where a signal intensity is maximized during a power-on process or validation check of the spectrophotometer;
• and
• an abnormality detector comparing the signal value acquired by the signal acquirer with the threshold value stored in the memory section and then determining that an operation is abnormal if the signal value exceeds the threshold value.