An identification information input support system supports a worker inputting identification information to a plurality of devices. The support system includes an information storage apparatus, and a mobile terminal. The information storage apparatus includes a communication unit that communicates with the mobile terminal, a storage unit that stores device information, and an update unit that updates the management information in response to input of the identification information. The device information includes the identification information, drawing information indicating location in which the device is installed, layout information indicating a layout of the device in the drawing information, and management information indicating a degree of progress of the task of inputting the identification information to the devices. The mobile terminal includes a communication unit that communicates with the information storage apparatus, and a display unit that displays the device information, the drawing information, and the layout information in association with each other.