An initialization-allowing communication system is constituted with devices 70 and 80, a controller 400 for controlling the devices 70 and 80 through communication, and so on. Each device and the controller 400 are provided with communication means 31, a house code showing a setting place, a subsystem ID showing the ID of a subsystem in a set system, a device ID showing the type of device, and self-address setting-holding means 11 for holding a self-address constituted with a device number showing a device number and the controller 400 is further provided with system structure holding means 301 for holding the information concerned with the system structure to be controlled and a communication-counterpart-address setting-holding means 401 for setting and holding the address of a counterpart to be communication-controlled obtained from the information concerned with the system structure.