The present invention provides a system used to confirm that a user of a mobile terminal device has visited a prescribed location, the system including the mobile terminal device and a server, the server including a control device and one or more wireless devices, wherein: the one or more wireless devices transmit a service notification; the mobile terminal device transmits a visit confirmation request; at least one wireless device transmits a task notification; the mobile terminal device executes a task on the basis of the task notification and repeatedly transmits a task completion notification; at least one wireless device transmits a solution request; the mobile terminal device transmits a solution notification; at least one wireless device receives the solution notification transmitted from the mobile terminal device; and the control device determines the legitimacy of the visit confirmation request on the basis of the solution notification.