Provided are a cooling method and a cooling apparatus that, in the cooling of a hot-rolled steel strip, regulates the amount of cooling water in a two-stage manner for each set of headers in the width direction and changes the rate at which the steel strip is cooled, in a multistage manner by a simple method, and that is effective particularly in cooling the lower surface of the steel strip, where space is narrow. The spray nozzles 5 are arranged in a row in the width direction of the steel strip at a predetermined pitch. Two systems of cooling headers 6 are arranged for one set so that spray nozzles 5 adjacent in the width direction can be supplied with cooling water from different pipe systems, and a spray valve 7 is attached to each cooling header 7 so that spraying/stop of spraying of cooling water can be individually performed.