An information processing system includes a plurality of node devices and a gateway device configured to communicate with the plurality of node devices. Each of the plurality of node devices is connected to a sensor configured to measure a state of a facility, and is configured to execute a measurement task. Each of the plurality of node devices is configured to add node identification information used to identify the node device and task identification information used to identify the measurement task executed by the node device, to measurement data acquired in the measurement task, and send the measurement data to the gateway device.