A system and a method are provided for specifying arbitrary nodes and identifying a section between them on a system diagram of a distribution system. It comprises a system diagram information management portion for managing information on each of nodes and spans constituting the system diagram and ID information given to each of the nodes, an input portion for receiving an input specifying the nodes, a search portion for creating a search condition using the ID information based on the node specification and searching the span between the specified nodes so as to identify the section constituted by the searched span, and an output portion for display-outputting the system diagram visually indicating the section identified by the search portion.