To permit higher priority to be given to the announcement of a call from a patient than to the announcement of another call even if the patient operates a nurse call extension unit for which the higher priority of announcement is not set in trying to inform that an emergency has occurred.

When calls from three or more nurse call extension units 1 overlap, when the priority of announcement of a nurse call extension unit 1 not belonging to the same group as the group which two or more nurse call extension units 1 belong to is higher than the priority of announcement of the two or more nurse call extension units 1, the nurse call system announces the calls in preference to the call from the nurse call extension unit 1 not belonging to the same group as the group which the two or more nurse call extension units 1 belong to. Consequently, when calls from at least two nurse call extension units 1 belonging to the same group overlap, the system decides that an emergency has occurred in an area corresponding to the group.