PURPOSE: To detect a hemolytic component in a blood serum by irradiating the blood serum part of a centrifugally separated object to be inspected with light and receiving the transmitted light with an integrating sphere.

CONSTITUTION: The blood collected in a blood collecting tube 1 is centrifugally separated into a clot composed mainly of red corpuscles and a supernatant blood serum 3. In case some red corpuscles are destroyed and remain in the blood, the component having a specific gravity which is nearly equal to that of the serum 3 does not move to the clot 2 section, but stays mixed in the serum 3. As a result, the serum 3 which is always colored in yellow becomes reddish in color. A convergent luminous flux is introduced into the tube 1 from a light source 4 through a lens 5 and the transmitted light is made incident to an integrating sphere 6 incorporating three detectors 7, 8, and 9 and BPFs 10, 11, and 12 in front of the detectors 7, 8, and 9. The intensities of the transmitted light obtained at, at least, three wavelength points are compared with each other and the hemolytic state of the object to be inspected is discriminated by setting levels based on the ratio of the intensities.