SPECTROPHOTOMETER

PROBLEM TO BE SOLVED: To provide a spectrophotometer by which the spectral measurement of the two dimensional area can be effectively performed with high accuracy in comparison with a conventional one. SOLUTION: The outgoing light from the outgoing bundles 18, 20 of three branch bundle-type optical fiber 12, illuminates a sample, and the outgoing light from an outgoing bundle 22 is detected by a monitor photodetector 8. A controlling unit 40 determines the detecting position and intensity of the monitor light on the basis of the detecting signal of the monitor photo detector 28, and analyzes the same to determine the distribution of the illuminance within the measurement area, so that the data on the intensity of the reflected light detected by a photodetector 34 can be properly corrected.