Abstract: A packet usage amount calculation device and a packet usage amount calculation method capable of calculating a usage amount of a local network from a home network side, when communication is performed using subscriber information for the local network. In a proxy device, a subscriber profile storage unit stores token information associated with the subscriber information (a local network number) of the local network and an SMS instruction unit transmits a token to a local network number destination. A connection reception unit receives token information and IP address information from a terminal device and a usage amount calculation unit calculates a usage amount on the basis of an IP address.