1. A reconfigurable data processing device comprising: first and second switches; a data transmission unit; first and second data processing units, a data output unit of the first data processing unit being connected to the data transmission unit via the first switch and a data input unit of the second data processing unit being connected to the data transmission unit via the second switch; a storage unit configured to store first configuration data for configuring the first and second data processing units such that the first and second data processing units perform a first data processing operation, and second configuration data for configuring the first and second data processing units such that the first and second data processing units perform a second data processing operation; a switching unit configured to switch contents of data processing executed by the first and second data processing units in accordance with the second configuration data; and a timing control unit configured to control timing of switching the contents of the data processing by the switching unit for the first and second data processing units such that the content of data processing executed by the first data processing unit is switched from the first data processing operation according to the first configuration data to the second data processing operation according to the second configuration data at a first timing according to an input of first data to the first data processing unit for performing the second data processing operation and such that the content of data processing executed by the second data processing unit is switched from the first data processing operation according to the first configuration data to the second data processing operation according to the second configuration data at a second timing according to an input of second data to the first data processing unit for performing the second data processing operation, wherein the first data processing unit executes the second data processing operation on the first data and the second data processing unit simultaneously executes the first data processing operation on data on which the first data processing operation has been executed by the first data processing unit in a time period between the first timing and the second timing, where the time period between the first and second timings occurs in a single clock cycle, and wherein the first data processing unit executes the second data processing operation on the second data and the second data processing unit executes the second data processing operation on the first data on which the second data processing operation has been executed by the first data processing unit after the second timing.