An intercom system for an apartment house, comprising: room units (10A, 10B) which are installed in respective rooms of the apartment house; and a control unit which is connected to the room units (10A, 10B) of the respective rooms via an intercom line so as to be capable of communicating therewith, and is capable of communicating with an external server via an external communication network, the control unit is configured to acquire, based on a request signal transmitted from the room unit via the intercom line, predetermined information corresponding to the request signal from the external server via the external communication network, and transmit the acquired predetermined information via the intercom line to the room unit which transmitted the request signal, characterized in that, the intercom line includes at least two communication channels, and the control unit is configured to check a use state of the intercom line when receiving the request signal, and to acquire the predetermined information from the external server when the intercom line has a vacant channel, and wherein, priority order is assigned to plural functions using the intercom line, the plural functions include an information acquiring function in which the room unit is configured to acquire the predetermined information from the external server via the control unit, and when a function having a higher priority than the information acquiring function is required to be used while the predetermined information is transmitted to the room unit via the intercom line, the control unit is configured to interrupt the information acquiring function and to release the channel of the intercom line having been used for the information acquiring function. room units (10A, 10B) which are installed in respective rooms of the apartment house; and a control unit which is connected to the room units (10A, 10B) of the respective rooms via an intercom line so as to be capable of communicating therewith, and is capable of communicating with an external server via an external communication network, the control unit is configured to acquire, based on a request signal transmitted from the room unit via the intercom line, predetermined information corresponding to the request signal from the external server via the external communication network, and transmit the acquired predetermined information via the intercom line to the room unit which transmitted the request signal, characterized in that, the intercom line includes at least two communication channels, and the control unit is configured to check a use state of the intercom line when receiving the request signal, and to acquire the predetermined information from the external server when the intercom line has a vacant channel, and wherein, priority order is assigned to plural functions using the intercom line, the plural functions include an information acquiring function in which the room unit is configured to acquire the predetermined information from the external server via the control unit, and when a function having a higher priority than the information acquiring function is required to be used while the predetermined information is transmitted to the room unit via the intercom line, the control unit is configured to interrupt the information acquiring function and to release the channel of the intercom line having been used for the information acquiring function.