This study empirically analyzed the spatio-temporal effect of the block-unit housing rearrangement project on neighboring housing prices in Seoul, where the need for housing supply is highest, based on the triple difference method. In particular, this study examined the microscopic effects of the project by estimating whether the price impact appear differently according to regions, particularly between Gangnam and non-Gangnam areas. The main results are as follows: First, it was found that the housing and complex characteristics had a similar effect on housing prices as in previous studies. Second, the block-unit housing rearrangement project in Seoul had a significant effect on nearby apartment prices. This implied that the project has a significant ripple effect on the local housing market in that it improved the physical environment of the area. Third, it was confirmed that the block-unit housing rearrangement project in the Gangnam area significantly increased the nearby apartment prices, when compared to the non-Gangnam area. This study confirmed that the small-scale housing improvement project such as the block-unit housing rearrangement project in Seoul has a significant effect on neighboring housing prices, and this effect can be differentiated and complex depending on the regional features.