There is provided with a bridging device that is connected to a first and a second network, including: a connection detecting unit that detects an appliance on the second network; a state holding unit that holds either a first or a second state; an arbitration unit that determines that the detected appliance is subjected to bridging processing in a case where the second state is held by the state holding unit, and, determines whether the detected appliance is subjected to the bridging processing on the basis of a predetermined confirmation condition where the first state is held by the state holding unit and, in a case where it is determined that the appliance is subjected to the bridging processing, sets the state holding unit in the second state; and a bridging unit that subjects the appliance, which is determined to be subjected to the bridging processing, to the bridging processing.