A user operates a selection panel installed in a shop to select contents which the user wants to review. A reception unit identifies the contents based on the user's operation on the selection panel, acquires an ID of a portable device incorporated in headphones worn by the user, and transmits the ID to a management server. The management server transmits data of the contents to a transmission device, which searches for a signal electrode capable of communicating with the portable device of the user among signal electrodes that are embedded in the floor of the shop. The transmission device transmits a signal representative of the contents from the signal electrode that has been searched for, and the portable device receives the signal transmitted from the transmission device. An audio signal of the contents is output from the headphones.