An apparatus for comminuting of material that includes a first conveyor structure with a first conveyor surface, a second conveyor structure with a second conveyor surface, and in which apparatus the first conveyor surface and the second conveyor surface are set facing each other. The conveyor surfaces are configured in a double-converging manner so that in addition to said convergence in the movement direction, the conveyor surfaces are additionally placed in a convergent manner so that the gap between the conveyor surfaces also narrows in the transverse direction in relation to the movement direction, such that the comminuting space becomes double-converging.