There is described a head box for a paper machine or the like, wherein a nozzle is adapted to apply a web-forming, fiber-containing pulp to a wire arrangement. The head box comprises a header to which said pulp is supplied, a tube bank including a plurality of tubes arranged side by side in the cross machine direction and connected to the header. Flow control elements are arranged in the tube bank for controlling flow passing through the individual tubes of the tube bank. Downstream of the tube bank is a turbulence generator which connects the tube bank to the nozzle. The turbulence generator has pulp channels having a cross-sectional shape which changes gradually between inlet and outlet of said turbulence generator. Preferably, the total internal wall surface as defined by the channel axial length and internal circumference length is set to generate a turbulent boundary layer of the pulp flow causing breaking of fiber flocks in the pulp so that e.g. the passage of each channel may be of stepless and aerodynamic shape.
