To reliably collect measured data without requiring a large-capacity storage device. A data collection device which is connected with a plurality of machine tools via a network includes: a priority calculation means for calculating a degree of relative priority for each of the plurality of machines tools, based on information related to a state of each of the machine tools; and a measured data collection means for deciding, in a case of receiving a collection request of measured data for the machine tool, which machine tool among the machine tools corresponding to the collection request to set as a collection target of the measured data based on the degree of relative priority, and for collecting the measured data from the machine tool decided as the collection target via the network.