A filtering and washing device has a filter body mounted in a housing for rotation about a horizontal axis and comprising a first portion in the form of a truncated cone or pyramid having a base plate with an eccentrically positioned polygonal orifice and a second portion in the form of a sawtooth-shaped tube rigidly connected at one end to the orifice and at an opposite end to a cylindrical drive shaft rotatably journaled in the housing and operationally connected to a motor, the tube in turn being formed from a multiplicity of hollow prisms or truncated pyramids. The first and second portions have surfaces provided with respective filter means. A pipe fixed to the housing traverses an end plate of the first portion opposite the base plate for rotatably supporting the filter body at one end and for feeding to the first portion material to be filtered or cleaned, while the tube is provided with an opening spaced from the base plate of the first portion for dispensing treated material. A multiplicity of articulated pipe sections extend through the drive shaft and inside the second portion for feeding a washing solvent thereto, filtrate from the tube being fed to the first portion via a collector, a conduit, a pump, a valve and a pipe coaxially disposed inside the feeder pipe. A further solvent-distribution pipe may be provided for washing outside surfaces of the filter body.