Abstract: A method and an apparatus for finely crushing particles of material in a mill comprising feeding the material to be crushed to a first impact position, impacting and impelling the particles from the first impact position by a rotating impact surface stationary impact surface to a and accelerating the particles in a vacuum to produce a sufficiently high impact energy at the first impact surfact to crush the particles fed thereto prior to the section impact surface. The particles to be comminuted are passed through a feeding tube or channel to a crushing chamber containing a rotor having its axle parallel to the feeding tube and having first impact surfaces thereon which are arranged to be parallel with the stationary impact surface, or surfaces, at the time they impact with the particles fed to the first impact position. The outlet of the feeding tube is located at the outer periphery of the rotor.