PURPOSE: to enable high speed measurement by preventing erroneous operation, by judging the quality of an article to be inspected by such a method that the article to be inspected is transferred by a pair of suction drums while the inside and outside thereof are reversed and the measured result of one drum is shifted to be combined with the measured result of the other drum.

CONSTITUTION: A pair of suction drums 1, 3 having concavities 2aW2d, 4aW4d for quantity a large number of solid preparations provided to the outer peripheral surfaces thereof are provided so as to cross at right angles, and cameras 5, 6 and light source 7, 8 are respectively arranged above said drums 1, 3. A measuring circuit consisting of discrimination circuits 10, 11 and shift circuit 12 is connected to the cameras 5, 6. After the surface of each preparation is photographed on the suction drum 1 by the camera 5, said preparation is transferred to the drum 3 while the inside and outside thereof are reversed and the back surface thereof is photographed by the camera 6 and respective specimen informations are sent to the discrimination circuits 10, 11. After the quality of the preparation was judged by the discrimination circuit 10, predetermined shift is performed by the shift circuit 12 and the judgement of the quality of the preparation is performed by the shifted judge result of the discrimination circuit 10 and the measured result of the discrimination circuit 11. By this method, no erroneous operation is generated even if the preparation is supplied in an inside and outside reversal state.