PURPOSE : A cadastral building space information fusion method with a comprehensive real estate system of unified real estate administration information is provided to apply a building boundary extraction algorithm and a cadastral building fusion algorithm to an arrangement map and a cadastral map of a building, thereby automatically extracting a boundary map based on the cadastral map.CONSTITUTION : A communication module(110) transmits a cadastral map. The communication module receives a building arrangement map based on the cadastral map. When the building arrangement map is satisfied with a reference format, an extraction module(130) extracts a cadastral boundary line and a building boundary line from the building arrangement map. The extraction module extracts the building boundary line. A fusion module(140) generates a building boundary map based on the cadastral map.[Reference numerals] (110) Communication module; (120) Verification module; (130) Extraction module; (140) Fusion module; (150) Storage module; (AA) Cadastral map and constructional cadastral map; (BB, CC) Building arrangement map; (DD) Building arrangement map, building boundary lines; (EE) Building cadastral mapCOPYRIGHT KIPO 2013