A cooling device of a hot-rolled steel sheet, comprising: a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of the hot-rolled steel sheet just after rolled by rolling stands (F1 to F7) in a hot-finish-rolling mill formed of a plurality of rolling stands (F1 to F7), wherein the nozzles are provided on the inside of both of guides or adjoining to the guides on a downstream side between the guides provided at upper and lower sides on an exit side of the rolling stands (F1 to F7), and the nozzle is a full cone nozzle or a thickening flat spray nozzle, a steel sheet design position of the hot-rolled steel sheet which is set between the upper and lower guides is used as a reference, and a nozzle spray distance along a spray center axis between a spray port of the nozzle and the steel sheet design position changes depending on a position of the nozzle in a rolling direction and an angle of the steel sheet design position of the hot-rolled steel sheet just after the rolling stands (F1 to F7) exists between "0" (zero) degree to an angle θ formed by the upper and lower guides, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large, the plurality of nozzles are arranged in a width direction to form columns, and the predetermined number of columns are put together in the rolling direction to form a plurality of nozzle groups arranged in the rolling direction, the number of the plurality of nozzle groups is the same as the number of columns in the rolling direction of the nozzles provided in the rolling direction at a maximum, a pipe where cooling water is supplied is connected to each of the nozzle groups, a three-way valve and a flow rate regulating valve are provided at each pipe, the three-way valve is disposed at a height lower than an upper end of the nozzle, the nozzles are provided on the inside of a cooling box, the inside of the cooling box is divided into a plurality of sections in a rolling direction, the pipe is provided at each section, and a tip of the pipe has a height lower than the upper end of the nozzle. a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of the hot-rolled steel sheet just after rolled by rolling stands (F1 to F7) in a hot-finish-rolling mill formed of a plurality of rolling stands (F1 to F7), wherein the nozzles are provided on the inside of both of guides or adjoining to the guides on a downstream side between the guides provided at upper and lower sides on an exit side of the rolling stands (F1 to F7), and the nozzle is a full cone nozzle or a thickening flat spray nozzle, a steel sheet design position of the hot-rolled steel sheet which is set between the upper and lower guides is used as a reference, and a nozzle spray distance along a spray center axis between a spray port of the nozzle and the steel sheet design position changes depending on a position of the nozzle in a rolling direction and an angle of the steel sheet design position of the hot-rolled steel sheet just after the rolling stands (F1 to F7) exists between "0" (zero) degree to an angle θ formed by the upper and lower guides, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large, the plurality of nozzles are arranged in a width direction to form columns, and the predetermined number of columns are put together in the rolling direction to form a plurality of nozzle groups arranged in the rolling direction, the number of the plurality of nozzle groups is the same as the number of columns in the rolling direction of the nozzles provided in the rolling direction at a maximum, a pipe where cooling water is supplied is connected to each of the nozzle groups, a three-way valve and a flow rate regulating valve are provided at each pipe, the three-way valve is disposed at a height lower than an upper end of the nozzle, the nozzles are provided on the inside of a cooling box, the inside of the cooling box is divided into a plurality of sections in a rolling direction, the pipe is provided at each section, and a tip of the pipe has a height lower than the upper end of the nozzle.