Communication control method, relay device and billing management apparatus

A gateway server 40, in the case that discontinuation of TCP Connection A between a portable phone 10 and gateway server 40 is detected when gateway server 40 is relaying HTTP communication between portable phone 10 and a content server 70, maintains TCP Connection B1 between a billing management server 50 and gateway server 40 until gateway server 40 receives from billing management server 50 billing information for HTTP communication relayed up to the time of the discontinuation of TCP Connection A.