An image storage portion 31 stores image data that is input. An outline detecting portion 32 detects an outline of tooth that is the object of color measurement in the image based on the image data. A specular reflection region detecting portion 33 detects the position of a specular reflection region in the tooth that is the object of color measurement based on the data of each pixel that constitutes the image. A rectangular region setting portion 34 sets an analysis region to become the object of analysis processing in the image based on the position of the specular reflection region that is detected by the specular reflection region detecting portion 33. In accordance with the present invention, it is possible to avoid setting an analysis region in a specular reflection region when setting an analysis region, that is the object of analysis processing of an image, in the image.
