An image input module inputs image signals which have different sampling rates. Based on a predetermined processing flow, a filter processing module carries out a filter processing by a predetermined filter factor on the image signals which are inputted by the image input module. A plurality of filter factors which are used at the filter processing module are set at a filter factor setting module. A filter factor selecting module selects, from among a plurality of filter factors, an appropriate filter factor in accordance with the sampling rates of the image signals and the processing flow, and supplies them to the filter processing module.