PURPOSE: To collect toner with low voltage loss and high collecting efficiency by constituting the titled element of an electret fiber-like sheet having electrostatic charge on its surface and provided with an electric field structure orientating the polarized charge constituting the surface charge in the thickness direction.

CONSTITUTION: Toner 2 stuck to the surface of a drum 1 is scraped by a fur brush 3, the dropped toner is collected by a cyclone 4 and small toner is collected by the filter element 5. The filter element 5 is constituted of the bag-like electret fiber-like sheet 7 and its fitting frame 8 and the sheet 7 has surface charge and its polarized charge is orientating in the sheet thickness direction. Non-woven fabric, waven fabric or paper are used for the sheet 7 and its surface charge density is preferably ≥7×10-11C/cm2. Consequently, straying toner and other dust can be efficiently collected.