To prevent the erroneous operation of a call button to certainly perform calling operation by only once operating the call button.

When the call button 3 is operated, it is acoustically guided that a call is performed and the operation of the call button 3 is canceled by again operating the call button 3. In a case that the call button 3 is operated within a predetermined time, the operation of the call button 3 is canceled and, in a case that the call button 3 is not operated within the predetermined time, a call signal is outputted to a nurse call master unit 10 to report the call. By this constitution, the operation of the call button 3 is canceled by again operating the call button 3 according to the content acoustically guided by the operation of the call button 3 and the erroneous operation of the call button 3 can be certainly prevented. Further, since the call is reported after the elapse of the predetermined time by only once operating the call button 3, the report of the call can be certainly performed without secondarily operating the call button 3.