Abstract: A network-based system for relaying contents for advertisement products includes a plurality of display devices for advertisement configured to display the advertisement products and represent identifiers which distinguish the advertisement products, respectively, and one or more mobile terminals for requesting for the relay of a content for an advertisement product of interest via a network by using an identifier of the advertisement product. A management server management server recognizes which content is for the advertisement product of interest based on the identifier from the mobile terminal, and relays the recognized content to the mobile terminal via the network to thereby interwork with the mobile terminal. The mobile terminal reproduces and searches for the content for the advertisement product relayed from the management server, and performs purchase of the advertisement product.