A data processing device capable of rapidly processing data through simple operations by the user without requiring a tape editor to be already executing when capturing data from a Web browser and supplying that data to the tape editor and without requiring the user to start up the tape editor. A data capture controller 22 captures prescribed data from the Web browser 31 in a data supply controller 23 based on operations of a keyboard 12 and/or mouse 13. The data supply controller 23 launches the tape editor 32 and supplies the captured data to the same. At this time, the process command unit 24 instructs the tape editor 32 regarding what process to execute, and printing by the tape printing device 2 is performed automatically.