Information on a communication relation or communication path to be monitored is automatically generated to reduce load of a user. A path information generation part receives a destination IP address designated by a user, through an input receiving part. When the input of the destination IP address is received, the path information generation part uses configuration information tables, each of which stores configuration information of a device on a network, to identify IP addresses of networks each having a plurality of terminals, as branch IP addresses. The path information generation part uses the configuration information tables and transfer destination information tables each storing a routing table of a router, to identify the connection order of routers between the designated destination IP address and the identified branch IP addresses, to generate path information.