A player has the function of viewing contents on an in-house network, without installing software in the player.A gateway apparatus mediating between the in-house network and the Internet is provided with a mediation program; the in-house network or the Internet is provided with a conversion server; the mediation program acquires a contents list from an Internet dynamic-image site and converts the contents list to a data format displayable by the player; the player displays the contents list to enable a user to make a selection; the mediation program transfers, to the conversion server, a contents acquirement request selected from the contents list displayed in the player; the conversion server acquires a dynamic image from the dynamic-image site, converts the dynamic image to a format regenerable by the player and transmits it to the player via the gateway apparatus; and the player regenerates the received dynamic-image data.