A data-flow control device comprising: a device-side metadata acquisition unit configured to acquire device-side metadata including an item indicating a specification of data that can be provided by a device for each of a plurality of devices, the device being a sensor configured to output sensing data an application-side metadata acquisition unit configured to acquire application-side metadata including an item indicating a specification of data requested by an application that uses the data provided by the device and the application being one of factory automation, production control and meteorological environment measurement; a storage configured to store the device-side metadata and the application-side metadata; a matching unit configured to perform matching between the application-side metadata and the device-side metadata to extract a combination of an application and a device capable of providing the data satisfying the specification required by the application; and a data-flow controller configured to generate a data-flow control command specifying the device and the application extracted by the matching unit and instructing transmission of the sensing data based on the information output by the matching unit to the application; characterized in that a flag indicating changeability is associated with each of matching target items included in the device-side metadata and the application-side metadata, and the matching unit is configured to extract the combination based on whether matching target items are matched with each other among the items included in the device-side metadata and the application-side metadata, when the item in which the mismatch is generated exists and the flags indicate that the item in which the mismatch is generated is changeable, inquire of both of a user who manages the device and a user who manages the application whether to change the item in which the mismatch is generated, wherein the device-side metadata is at least one of a sensing target, a location and a region to be sensed, a sensing time, a data type of the sensing data, a data format, and a sensing condition, and wherein the application-side metadata is at least one of a sensing target, an area to be sensed, a sensing time, a data type of the sensing data, a data format, and a sensing condition. a device-side metadata acquisition unit configured to acquire device-side metadata including an item indicating a specification of data that can be provided by a device for each of a plurality of devices, the device being a sensor configured to output sensing data an application-side metadata acquisition unit configured to acquire application-side metadata including an item indicating a specification of data requested by an application that uses the data provided by the device and the application being one of factory automation, production control and meteorological environment measurement; a storage configured to store the device-side metadata and the application-side metadata; a matching unit configured to perform matching between the application-side metadata and the device-side metadata to extract a combination of an application and a device capable of providing the data satisfying the specification required by the application; and a data-flow controller configured to generate a data-flow control command specifying the device and the application extracted by the matching unit and instructing transmission of the sensing data based on the information output by the matching unit to the application; characterized in that a flag indicating changeability is associated with each of matching target items included in the device-side metadata and the application-side metadata, and the matching unit is configured to extract the combination based on whether matching target items are matched with each other among the items included in the device-side metadata and the application-side metadata, when the item in which the mismatch is generated exists and the flags indicate that the item in which the mismatch is generated is changeable, inquire of both of a user who manages the device and a user who manages the application whether to change the item in which the mismatch is generated, extract the combination based on whether matching target items are matched with each other among the items included in the device-side metadata and the application-side metadata, when the item in which the mismatch is generated exists and the flags indicate that the item in which the mismatch is generated is changeable, inquire of both of a user who manages the device and a user who manages the application whether to change the item in which the mismatch is generated, wherein the device-side metadata is at least one of a sensing target, a location and a region to be sensed, a sensing time, a data type of the sensing data, a data format, and a sensing condition, and wherein the application-side metadata is at least one of a sensing target, an area to be sensed, a sensing time, a data type of the sensing data, a data format, and a sensing condition.