A comminution plant for comminuting material includes a set of fixed bottom knifes separated by parallel opening, two parallel shafts extending crosswise of the openings, a set of upper knifes attached on respective shafts and extending partly into the openings, and at least one drive assembly for rotating the shafts during operation. The upper knifes on one shaft include first and second knifes with the second one having a diameter which is smaller than the first. The upper knifes on the other shaft includes third and fourth knifes with the fourth one having a diameter which is smaller than the third. The diameters of the first and third knives are of a size which is larger than twice the distance between the axes of rotation of the at least two shafts. The comminution plant according to the invention can comminute a material effectively and to high degree of fineness.