Devices and systems are provided to determine the condition of a subject comprehensively on the basis of a measurement result of a body water meter. The body water meter measures the amount of water in a subject's body and includes direction means and output means. The direction means, when water amount data is acquired through the measurement of the amount of water, directs a server that manages data regarding living body information on the subject to search for another piece of data acquired through measurement of living body information on the subject other than the amount of water and that satisfies a predetermined measurement condition. The output means outputs a message indicating the condition of the subject which is determined on the basis of the water amount data and the other piece of data on the subject received in response to the direction from the direction means.