1. A method for extracting at least one representative color signal value representing each color region from each of a plurality of color regions in a color chart image comprising the steps of: a region deciding step of deciding a color signal value extracting region for each color region of said color chart image; an extracting step of calculating said representative color signal value of said color region on the basis of color signal values in said color signal value extracting region and extracting the same; a displaying step of displaying said color signal value extracting region along with said color chart image on a display unit; and a determining step of determining correctness of said representative color signal value on the basis of said color signal value extracting region and said color chart image which are displayed on said display unit.