To provide a nurse call system capable of giving an alarm of a mobile medical device at a nurses station, automatically detecting a signal mode of the medical device, and detecting a connection failure of the medical device.

An artificial respirator 6 is connected to a nurse call handset 1 through a nurse call adapter 5. The nurse call adapter 5 includes a contact determining circuit 13 to determine whether an output signal of the artificial respirator 6 is a make contact or a break contact, a calling circuit 4 to receive and convert the output signal of the artificial respirator 6 so as to be received by a nurse call base unit 3, and to output it, and a dropping and breaking detection circuit 16 to detect dropping or breaking of a connecting part of the artificial respirator 6.