Spatial light measuring method and spatial light measuring system

A spatial light measuring system is disclosed, which is configured to store illuminance data acquired by measurement in a new state as initial data, to make the traveling vehicle run after acquiring the initial data, to save illuminance data acquired by the illuminance measuring instrument as daily management data, and to specify an illuminance measuring position and an image acquiring position based on the speed of the traveling vehicle and to use a correction coefficient due to a distance from the ground to an illuminance measuring instrument mounting position and a correction coefficient due to the speed of the traveling vehicle and is configured to correct daily management data into illuminance data on the ground based on both the correction coefficients and to judge the soundness of the illumination facility based on a comparison between the illuminance data as corrected, the initial data and based on the images as acquired.