A monitoring device monitors facility elements in a building. Self-localization of the monitoring device is estimated by collating measured three-dimensional shapes with a map for localization including the shapes and positions of structural objects inside a building excluding the shapes and positions of facility elements. The monitoring device extracts the shape and position of a facility element candidate from the measured three-dimensional shapes; and calculates a similarity between the shape and position of each of the facility elements in the periphery of the self-localization extracted from the facility element collation map. The monitoring device identifies which of the facility elements in the periphery of the self-localization extracted from the facility element collation map is the facility element candidate extracted from the measured three-dimensional shape on the basis of the calculated similarity.