An apparatus for descaling hot rolled stock (17), being moved with respect to the apparatus, by spraying it with high pressure water, comprising at least one row of nozzle heads sweeping across the width of the rolled stock with a plurality of nozzle heads (20), each nozzle head being motor-driven in rotation about an axis of rotation (A) substantially perpendicular to the surface of the rolled stock and comprising at least two nozzles (1 to 8) which are disposed eccentrically with respect to the axis of rotation (A) is characterized by the nozzles (1 to 8) of each nozzle head (20) being arranged as closely as structurally possible to the circumference (25) of the nozzle head, whereby a spray pattern is created on the surface of the rolled stock in a way to at least touch the spray pattern of the adjacent nozzle head in the row of nozzle heads.