Network quality monitoring device and method for internet services involving signaling

A network quality monitoring device includes a packet receiving unit that receives packets used by a signaling protocol server device that is a server device for processing the signaling protocol, a signaling protocol packet extracting unit that extracts signaling protocol packets for controlling the signaling protocol from packets received by the packet receiving unit, a session management table storing unit that stores the session management tables, a signaling protocol quality analyzing unit that collects quality information regarding the network quality from a session management table corresponding to sessions that have transitioned to a predetermined communication state among the session management tables stored in the session management table storing unit and, based on the collection result, analyzes statistical information regarding the network quality.