A device and a method for cooling metal strips or sheets conveyed on a conveyor line, in particular hot-rolled strips in the outlet of a rolling train. For these purposes, the device includes at least one cooling beam extending across the width of the conveyor line, and the cooling beam features a connection point to which a supply tube for cooling liquid can be connected, and a number of discharge openings arranged along a longitudinal axis of the cooling beam, such that cooling liquid can be discharged through the discharge openings in the direction of the metal strip or sheet that is to be cooled. Associated with each of the individual discharge openings is a respectively adjusted flow area, such that the flow areas of the respective discharge openings decrease in a direction leading away from the connecting point along the longitudinal axis of the cooling beam.