<p>A cooling device for a thick steel plate, the cooling device having pairs of restraining rollers, each pair having an upper roller and a lower roller between which the steel plate hot rolled is passed while being restrained, and also having spray nozzles for spraying water to the upper and lower surfaces of the steel plate passed between the restraining rollers adjacent to each other in the forward-rearward direction of plate passage. The spray nozzles are arranged in the following way: (1) The total area of an impingement surface on which water jet flows coming from the spray nozzle on the upper surface side impinge is in the range of 4 - 90% of the steel plate surface area between outer circumferential surfaces of rollers the distance between which rollers is the smallest among the distances between the pairs of restraining roller, and (2) The total area of an impingement surface on which water jet flows coming from the spray nozzles on the lower surface side impinge is in the range of 4 - 100% of the steel plate surface area between outer circumferential surfaces of rollers the distance between which rollers is the smallest among distances between the pairs of restraining roller.</p>
