PURPOSE: To qualitatively enhance the qualitative evaluation of illumination visible environment in a general indoor illumination field such as an office or a council room, by evaluating the discomfort glare of indoor illumination equipment from the depth of a room, the height of a ceiling, the light distribution characteristic of an illuminator, planning illuminance or the like.

CONSTITUTION: In the International Commission on Illumination (ICI), a chart for evaluating the discomfort glare of indoor illumination is determined as shown by drawing. That is, the degree of the discomfort glare of an illuminator is classified into eight levels from (a) to (h) from the brightness value of the illuminator within an angle-of-radiation range of 45W85° to show an unpleasant feeling. According to this chart, the angle of radiation of the illuminator at the center of equipment is obtained at first from the depth of a room and the height of a ceiling by an operator 1 and this value is sent to a judge device 2 and, from said value and the light distribution characteristic of the illuminator, the brightness at the center of the room of the angle of radiation obtained by the operator 1 is obtained. Thereafter, it is judged what curve among limit curves (a)W(h) this brightness belongs to and, from the classification obtained by the judge device 2 and the value of planning illuminance, an evaluation device 3 evaluates what degree in discomfort glare degree AWE said brightness belongs to.