To provide a hair coloring system which enables hair coloring treatment giving a hair color desired by a customer with stable quality based on the brightness of his own hair and gives effects of remarkably improving the satisfaction degree of a customer and the management efficiency on the beauty salon side.

Panels Pi to P5 are prepared for each step of the previously determined hair brightness, a classification color classified based on chroma, brightness, a hue, or the like is determined for each panel, drugs and a preparation ratio to be employed upon hair coloring treatment previously obtained by experimental treatment are previously set for each of the classification colors, after it is determined that the brightness of hair of a customer belongs to which color of the previously determined hair colors, drugs and a preparation ratio to be employed upon the hair coloring treatment are determined based on the classification color which is set for each of determined colors and is selected by a customer, and hair coloring treatment is performed.