To analyze the shapes of brown rice and polished rice a series of measurements by image processing on Japonica, Indica and Javanica types composed of four rice varieties with three polishing methods were carried out. Area, perimeter; maximum length, maximum width, compactness and elongation were measured. The maximum length, maximum width and elongation of a rice particle defined here were different from the traditional dimensions such as length and width. Further separating the rice varieties by the shape difference of a rice particle was examined. From the result of the investigation on brown rice and polished rice, separating the rice varieties was possible at a probability level of 95.4% with combined dimensions and shape factors or with single ones.