Abstract: In the optical inspection apparatus according to the invention, in a case where an optical change such as white turbidity and white sedimentation, or fluorescence is caused to a sample accompanying the reaction of amplifying an object to be inspected present in a sample tube, sample tubes are stood and arranged in a plurality of arrangement holes formed in a reaction block, an inspection light is irradiated to the respective sample tubes passing through the observation holes formed to the lateral surface or the holes formed in the bottom and optical change such as white turbidity and white sedimentation or fluorescence caused in the sample tube are detected based on the luminance distribution or the chromaticity distribution of image data photographed by the image pick-up camera thereby enabling accurate and rapid inspection for the presence or absence of an object to be inspected.