A distributor of a doorphone system including a lobby interphone for a visitor to an apartment house to call residents of visiting places, room monitors for the residents to respond by receiving a call from the visitor, and distributors that relay between the lobby interphone and the room monitors, in which the lobby interphone is connected to one of the distributors via a two-wire cable, the distributors are connected to each other with daisy chain type wiring via two-wire cables, and each of the distributors is connected to the room monitors via two-wire cables, the distributor comprising: a first terminal that is connected to the lobby interphone or a distributor at a preceding stage; and a plurality of second terminals (T321, T322, T323, T324) that are connected to the plurality of room monitors with star-type wiring; characterized by further comprising: a storage that stores key numbers allocated to the room monitors connected to each of the second terminals (T321, T322, T323, T324) in association with numbers of each of the second terminals (T321, T322, T323, T324); a relay unit (309, 310, 311) that opens and closes a communication path between the first terminal and any one of the second terminals (T321, T322, T323, T324); and a controller that determines whether or not a key number included in a signal input from the lobby interphone or the distributor at the preceding stage matches any one of the key numbers stored in the storage to control the relay unit (309, 310, 311) so that the communication path between the second terminal connected to the room monitor with the matched key number and the first terminal is opened. a first terminal that is connected to the lobby interphone or a distributor at a preceding stage; and a plurality of second terminals (T321, T322, T323, T324) that are connected to the plurality of room monitors with star-type wiring; characterized by further comprising: a storage that stores key numbers allocated to the room monitors connected to each of the second terminals (T321, T322, T323, T324) in association with numbers of each of the second terminals (T321, T322, T323, T324); a relay unit (309, 310, 311) that opens and closes a communication path between the first terminal and any one of the second terminals (T321, T322, T323, T324); and a controller that determines whether or not a key number included in a signal input from the lobby interphone or the distributor at the preceding stage matches any one of the key numbers stored in the storage to control the relay unit (309, 310, 311) so that the communication path between the second terminal connected to the room monitor with the matched key number and the first terminal is opened. a storage that stores key numbers allocated to the room monitors connected to each of the second terminals (T321, T322, T323, T324) in association with numbers of each of the second terminals (T321, T322, T323, T324); a relay unit (309, 310, 311) that opens and closes a communication path between the first terminal and any one of the second terminals (T321, T322, T323, T324); and a controller that determines whether or not a key number included in a signal input from the lobby interphone or the distributor at the preceding stage matches any one of the key numbers stored in the storage to control the relay unit (309, 310, 311) so that the communication path between the second terminal connected to the room monitor with the matched key number and the first terminal is opened.