An information management system which reduces the possibility of degradation of information management efficiency, an information management method, and an information management program are provided. In an information management system which includes a plurality of terminal devices to configured to generate detection data, a plurality of repeaters configured to acquire the detection data from at least one of the plurality of terminal devices, and a server configured to give and receive data to and from at least one of the plurality of repeaters, the plurality of repeaters respectively receive the detection data in advance from at least one of the plurality of terminal devices, the plurality of repeaters respectively hold terminal device lists, and the terminal device lists indicate at least one of the plurality of terminal devices from which the detection data is received and latest receipt time which is time at which the detection data is received.