An information exchange system includes a first mobile terminal device having publication notification request unit to request a publication notification, and information notification unit to transmit, upon receiving a publication request, the particular information to a mobile terminal device that sent the request; a second mobile terminal device having publication notification unit to send a publication notification to a mobile terminal device registered in a registration information storing unit; and a third mobile terminal device having information obtaining unit to send a publication request for the particular information to the first mobile terminal device to obtain the specific information from the first mobile terminal device.