A determining portion first determines which an interpolation pixel position (a target position of image signal) which is positioned in a field that precedes a current field by one field is included in a motion region or a still region by using an image signal of current field and an image signal of two fields before to obtain a determine result of this time. The determining portion finally determines which the interpolation pixel position is included in a motion region or a still region based on the determined result of this time and the history information, which is read out of a memory through a history-information-read-processing portion, on a determined result of past predetermined times(s) corresponding to the interpolation pixel position to obtain a determined result. The memory stores the history information on a determined result of past predetermined times(s) corresponding to each interpolation pixel position.