A two-dimensional filter arithmetic device comprises a picture memory, a line memory, a vertical filtering unit which includes nine first filter modules installed in parallel, a buffer for timing adjustments, and a horizontal filtering unit which includes four second filter modules installed in parallel. From the line memory, the pixel values of nine full pels per line are inputted in parallel to the vertical filtering unit, nine vertically-filtered values of half pels are generated and inputted to the horizontal filtering unit; thereby, four two-dimensionally-filtered values of half pels are generated.