A safety system according to the present invention includes an on-ship system which is provided on a ship and a land system which is provided on land. The on-ship system and the land system each obtain, from a safety detection device and a safety maintenance device which are provided on a ship, data which has been detected by the safety detection device and a signal which indicates a state of the safety maintenance device, and, on the basis of the obtained data and signal, transmit to the safety maintenance device a control signal for controlling the safety maintenance device.