It is indispensable to understand the luminance distribution to evaluate visual environment. The luminance measurement with a digital camera which installs the fish-eye lens can measure the range of 180 degrees at the same time. It is a practicable measurement method excellent as for operativeness and the portability. The measurement result can be recorded as one fish-eye image by converting the luminance value into color information and allocating it to each pixel. It becomes easy to use for various visual environment evaluations. This report describes the method of calculating effective luminance at the center of view from this fish-eye image. As a result. easily understanding effective luminance on the site which had complex luminance distribution became possible.