PURPOSE: To relax the degree of fatigue of the optic nerve by providing a recessed part of athletic sports court line width on the floor surface, containing a lamp implement at an equal interval in this recessed part, and also, covering it with an opaque plastic plate and forming it to the same surface as the floor surface, and containing a changeover switch and a dimmer in a power source control box.

CONSTITUTION: At the time of forming and displaying an athletic sports court line on the floor surface 1, when a power source is turned on by switching, for instance, to a volley ball court line from among many athletic sports court lines in order to set a changeover switch 6 contained in a power source control box 5, a light implement 3 in the floor surface recessed part 2 is turned on at an equal interval, and the volley ball court line is formed and displayed. Subsequently, illuminance of the lamp implement 3 is controlled by a dimmer 7 contained in the power source control box 5, and brightness of the formed and displayed volley ball court line is controlled. In such a way, the degree of fatigue of optic nerve is relaxed in all of an umpire, players, and spectators.