Abstract: A first recorder can be connected to a network. A recorder information acquisition unit acquires state information of a second recorder connected to the network. In a case where the second recorder is in a normal state, a camera information setting unit registers any of unregistered first to third cameras to the second recorder being in the normal state within a range of the settable number of ordinary channels on the basis of the acquired state information. In a case where the second recorder is in an abnormal state, the camera information setting unit substitutively registers any of the first to third cameras registered to the second recorder even in a range of the number of substitute channels.