Disclosed are a content providing system and a relay apparatus in which an information terminal connected to a multi-function mobile telephone receives a content in the same operational procedure as that for the multi-function mobile telephone. When a video gaming machine connected to the multi-function mobile telephone accesses a content providing apparatus, an DNS server in an NOC converts a telephone number of the multi-function mobile telephone into an ID code unique to the multi-function mobile telephone. The content providing apparatus thus identifies the multi-function mobile telephone in use, and a user can thus enjoy a video game on the video gaming machine in the same operation as that for the multi-function mobile telephone.