The invention provides a hot straightener, which comprises a plurality of parallel straightening rollers, and also comprises a plurality of groups of cooling devices for cooling different straightening rollers, wherein each group of cooling devices comprises a cooling tube, a nozzle which is arranged on the cooling tube and used for spraying a cooling medium in the cooling tube to the straightening rollers, a first medium pipeline and a second medium pipeline which are respectively communicated with the cooling tube to input different cooling mediums into the cooling tube, a first valve which is arranged on the first medium pipeline, and a second valve which is arranged on the second medium pipeline. According to the hot straightener, due to the arrangement of different cooling medium convey pipelines, the straightening rollers can be cooled in different manners, namely, the straightening rollers are directly cooled by cooling water, the cooling effect of the straightening rollers is further increased, while the wear of the straightening rollers is lowered, the affect of the straightening rollers on the quality of the steel plate is avoided by combining cooling by compressed air.