An intermediate transfer belt cleaning unit includes a cleaning blade put in sliding contact with the surface of a circulating intermediate transfer belt and a blade holder for holding the blade, the cleaning blade having a length extending across the width of the intermediate transfer belt, the blade holder being formed along the full length of the cleaning blade, for cleaning the surface of the intermediate transfer belt by means of the cleaning blade. In this cleaning unit, the contact pressure of the cleaning blade against the intermediate transfer belt is adjusted so that the contact pressure around both the side edges of the intermediate transfer belt is higher than the contact pressure in the remaining part.