Vacant house is one of the physical results caused by the decrease of population and housing demand in declining areas, and the number of vacant houses is over 1,510,000 according to the data of the year 2019 from the National Statistics Office. With the aging of the society as well as the natural reduction of the population starting in 2020, the increase of vacant houses is unavoidable in declining areas where there is no new

demand for housing. The vacant houses, concentrated in declining areas, are considered as the subjects of management, because they give a negative impression on the neighboring areas, accelerate the declining of the areas, and cause the hollowing of the areas.