A coin detecting apparatus comprising: - a light source for emitting a light beam onto either of two surfaces of a coin; - a half mirror for splitting the light beam reflected on the surface of the coin into a transmitted light beam and a reflected light beam; - a first image-capturing section for obtaining a full image of the surface of the coin in accordance with one of the transmitted light beam and the reflected light beam; - a second image-capturing section for obtaining an image of a central portion of the coin in accordance with the other one of the transmitted light beam and the reflected light beam, said second image-capturing section having a higher resolution than that of the first image-capturing section; and - an image-processing section which is provided with a storage section for storing full images corresponding to both sides of each coin and partial images having high resolution corresponding to central portions of each coin, a full image comparison section for comparing the full image of one of two surfaces of the coin input from the first image-capturing section with the full images previously stored in the storage section by rotating the full images previously stored, and a partial image comparison section for comparing the partial image of the central portion of one of two surfaces of the coin input from the second image-capturing section with the partial images previously stored in the storage section by rotating the partial images previously stored, wherein - the image-processing section determines whether comparison results of the full image comparison section and of the partial image comparison section correlate, and confirms a type of coin if the comparison results correlate with the full image comparison section and the partial image comparison section, - a lens is disposed between the half mirror and the second image-capturing section - comparison processed by the full image comparison section and comparison processed by the partial image comparison section is carried out in parallel, and - the resolution of the partial images and image area of the partial images are predetermined so that at least patterns of the central portion of the coin are capable of being captured as an image; and the data size of the captured image is less than or equal to that of the full images. - a light source for emitting a light beam onto either of two surfaces of a coin; - a half mirror for splitting the light beam reflected on the surface of the coin into a transmitted light beam and a reflected light beam; - a first image-capturing section for obtaining a full image of the surface of the coin in accordance with one of the transmitted light beam and the reflected light beam; - a second image-capturing section for obtaining an image of a central portion of the coin in accordance with the other one of the transmitted light beam and the reflected light beam, said second image-capturing section having a higher resolution than that of the first image-capturing section; and - an image-processing section which is provided with a storage section for storing full images corresponding to both sides of each coin and partial images having high resolution corresponding to central portions of each coin, a full image comparison section for comparing the full image of one of two surfaces of the coin input from the first image-capturing section with the full images previously stored in the storage section by rotating the full images previously stored, and a partial image comparison section for comparing the partial image of the central portion of one of two surfaces of the coin input from the second image-capturing section with the partial images previously stored in the storage section by rotating the partial images previously stored, wherein - the image-processing section determines whether comparison results of the full image comparison section and of the partial image comparison section correlate, and confirms a type of coin if the comparison results correlate with the full image comparison section and the partial image comparison section, - a lens is disposed between the half mirror and the second image-capturing section - comparison processed by the full image comparison section and comparison processed by the partial image comparison section is carried out in parallel, and - the resolution of the partial images and image area of the partial images are predetermined so that at least patterns of the central portion of the coin are capable of being captured as an image; and the data size of the captured image is less than or equal to that of the full images.