A color classification method including: determining a plurality of predetermined process target regions from a plurality of pickup images taken by an imaging device; calculating a plurality of color distributions of pixels contained in the respective determined process target regions; and forming a plurality of clusters by executing a clustering process based on the calculated color distributions for the pickup images, the method being for classifying a plurality of colors with respect to the respective formed clusters, the forming step including: extracting predetermined number of the classified colors, whose calculated rates are highest in the calculated plurality of the rates, from among the predetermined classified colors; defining a plurality of color spaces, dimensions of each of which are selected from the predetermined number of the extracted classified colors.