A dust-screening member is shaped like a plate as a whole. A vibrating member is adjacent to one side of the dust-screening member, arranged on the surface along the one side, and configured to produce, at the surface, vibration having a vibrational amplitude perpendicular to the surface. A drive unit is configured to drive the vibrating member to produce the vibration on the surface, such that peak ridges of the vibration form a closed loop and an area including a center of the closed loop is surrounded by a node area having almost no vibrational amplitude. When a length of a side in a dust-screening member virtual rectangle corresponding to a long side of a vibrating member virtual rectangle is assumed to be LF, and a length of a long side in the vibrating member virtual rectangle is assumed to be LPFF, LPFF/LF has a dimension of 0.7.