Abstract: The objective is to provide a technique that facilitates deciding on the lighting conditions of a lighting device illuminating an exhibit. A lighting device (A-1) illuminates a mannequin exhibited in a show window. A portable communication terminal (20A) captures an image of the mannequin and displays the captured image (28) of the mannequin. The portable communication terminal (20A) receives designation of a desired position on the mannequin in the displayed captured image (28) and acquires a color codeword that identifies the color in the captured image (28) for the designated desired position. A server (40) refers to a lighting condition database (61) storing a plurality of lighting conditions associated with a plurality of colors to determine the lighting condition associated with the color codeword acquired by the portable communication terminal (20A).