A house change judging method is provided for judging a change of a house in a data acquisition region based on new and old data concerning two periods, which have been aerially acquired, including: extracting as a judgment target region a predetermined region in the new data by trimming with house polygon data corresponding to a predetermined region prepared in advance; computing, after the extraction, as evaluation values, two kinds of new and old difference values between the two periods with respect to a gradation value of color image data and an altitude value of altitude data across the entire judgment target region; and judging, after the computation, based on the evaluation values, whether a house change has occurred in the judgment target region by referring to a judging table including combinations of two kinds of preset evaluation criterion values.