PURPOSE: To perform accurate judgement even if reflection conditions from tablets of plural production lines are different, by preliminarily picking up the image of a standard solid preparation and applying photoelectric conversion to each required part thereof to store the same while picking up the image of a solid preparation to be inspected under the same condition to compare each required place.

CONSTITUTION: At first, a standard tablet 1S is attached to a suction drum 2a and light is projected to said tablet 1S by a stroboscopic lamp 4a at the time of a predetermined rotary position to receive the image thereof by an image pick-up machine 3a while each required place is divided and subjected to photoelectric conversion to be stored in a memory circuit 5 and, subsequently, the tablet 1S is turned backside out to be adsorbed by a drum 2b and the image of the exposed surface of the tablet 1S is picked up in the same way by an image pick-up machine 3b to be stored in the circuit 5. Then, a tablet to be inspected is attafhed to the drum 2a and the image thereof is picked up by the image pick-up machine 3a and the each image receiving part is divided to be compared with the numerical value stored in the circuit 5 by a comparing circuit 6 to discriminate quality while the image of the back surface of the tablet is picked up in the same way and compared by the circuit 6 to discriminate quality. By this method, effect by the difference of the reflection condition of each tablet can be prevented.