The present invention provides a technique for changing the number of taps in filter processing without the need for execution of branch processing. A filter processing device comprises: an arithmetic circuit that performs arithmetic processing for filtering operation; an internal register that retains data to be subjected to arithmetic processing in the arithmetic circuit and that receives the result of arithmetic processing from the arithmetic circuit as data to be written back thereto; and a data generator that generates data to be fed to the arithmetic circuit through use of the data retained in the internal register. Further, in the filter processing device, there is disposed a tap number control circuit that is capable of controlling the number of taps in filter processing according to a tap control signal applied thereto. In this configuration, no branch processing is required for controlling the number of taps by the use of the tap number control circuit.