A data relay system in accordance with the present invention comprises: a database section 35 which is configured to store identification information for identifying language-dependent data and replacement data corresponding to the language-dependent data in association with each other; a server data receiving section 36 which is configured to receive server data from the server system 1; a data processing section 34 which is configured to detect the replacement data from the database section 35 on the basis of the identification information contained in the server data; a data generating section 37 which is configured to replace the language-dependent data as contained in the server data by the replacement data; and a client data transmitting section 38 which is configured to transmit the server data as replaced to a client system 2. In accordance with the present invention, even in the case where the language used in the server system 1 providing a service on the Internet is different from the language used in the client system 2, it is possible to recognize the information from the server by the client with reference to the replacement data.