To build up a plastic processing tool for processing symmetrically rotate working material so as to reduce hertzian pressure.

A plastic processing tool 1 has eccentrically arranged two rolling elements 2, 3 the eccentric rate e of which is adjustable in a way that a passage between the rolling elements in the narrowest position agrees with a diameter to be attained when the elements are deformed. The elements 2, 3 are rotatably supported by outside rings 6, 7 and the elements 2, 3 and the rings 6, 7 are slanted in a manner that a working face exists on a plain surface and, thereby, an inclined movement can be avoided. Also, the elements 2, 3 and the rings 6, 7 are supported by a tool base 10 so as to be swingably rotated by a rotation driving. Especially, an angle α formed by a contacting point line between the elements 2, 3 and a working element 14 and, an ordinary axial line is adjustable between 0° and 90°. A helical-like forward movement is thus made possible.