PURPOSE: To make judgement about the color, shape or the like of parts at high speed by saving as small data related thereto as possible in a storage memory.

CONSTITUTION: One type of output signals from a color image pick-up device 1 for photographing parts is converted to digital signals via an A/D converter 25, and binarized in a binary coding circuit 27. The binarized signals are, then, stored in a binary coded memory 29 as data related to the shape of the parts. On the other hand, the other type of output signals or three-primary color signals from the device 1 are alternately outputted to an A/D converter 39 through an analog switch 37 controlled with a synchronous signal separation circuit 33 and a tertiary counter 35. Also, the A/D converter 39 converts the signals to digital signals, and a color density memory 41, upon receipt of output therefrom, stores data related to color. CPU 13, then, makes judgement about the color or shape of the parts on the basis of the stored data.