An object of the present disclosure is to provide a data collection system capable of collecting various pieces of metadata other than sensing data and instrument information by existing communication protocols and associating the sensing data, the instrument information, and the metadata with each other without errors. A data collection system 301 is a data collection system that performs communication from a terminal 11 to a data collection unit 12 by one or a plurality of communication protocols, in which the terminal 11 includes a detection unit 11e other than a sensor device 11a that detects the sensing data and the instrument information, and stores metadata that is information detected by the detection unit 11e in an extended field specified by the communication protocols within a frame specified by the communication protocols for transmitting the sensing data or the instrument information, and the data collection unit 12 associates the sensing data, the instrument information, and the metadata with each other based on information for identifying the terminal 11 described in the frame.