A method for measuring a radio wave propagation environment includes installing radio signal transmission and reception apparatuses where a radio network system is to be constructed and obtaining an electromagnetic wave measured value of a signal between transmission and reception apparatuses; estimating an electromagnetic wave propagation state of the signal using an electrical property and information on a three-dimensional structure at the site to obtain an electromagnetic wave estimated value; making a comparison between measured and estimated values for each time of day to determine when errors between measured and estimated values exceed a reference value; obtaining an electromagnetic path between transmission and reception apparatuses; and modifying structure information in the wave path to re-obtain the estimated value; and comparing the measured re-obtained estimated value to modify the three-dimensional structure information so that the error value becomes smaller.