To provide an automatic teller machine monitoring system for protecting an automatic teller machine from a crime and illegality.

An automatic teller machine monitoring system judges compatibility between schedule information of maintenance work of maintenance work registered in advance (a scheduled working time, a guard man ID, working contents, etc.), and working information of actually executed maintenance work (an unlocking time (opening time), a locking time (closing time), the guards man IC, working contents). When the schedule information is not matched with the working information, the system judges an automatic teller machine 10 to be abnormal. Thus, when a guards man capable of opening the door of the machine 10 opens the door of the machine 10 excepting for the scheduled time of the maintenance work, the abnormality of the machine 10 is detected, so that illegality by the guards man is prevented. In addition, eve if the guards man opens the door of the machine 10 within the schedule time of the maintenance work, illegality by the guards man is prevented since the ID of the guards man is recorded.