To recognize characters described on a circumference and to automatically inspect them by scanning the characters of a date, etc., described on the circumference of the bottom, etc., of a battery in the circumferential direction with a central position found by reading an image as the center, extending it in a rectangular shape and inspecting the character through matching with a registered pattern when recognizing and inspecting the character described on the circumference of a medium.

A character 2 described on a medium 1 is scanned and read, the outer periphery of the medium 1 described with the character 2 is detected on a read image 3, and its central position is detected. Then, scanning is successively performed in the circumferential direction with this central position as the center, the image 3 is extended in the rectangular shape and afterwards, the previously registered pattern is used to apply pattern matching to the image 4 extended in the rectangular shape. Thus, the quality of a product is discriminated.