To prevent precision in coiling temp. control from degrading resulting from change of operation condition in a hot rolling mill and to stably obtain a strip metal plate having desired mechanical property.

The temp. control device is constructed so that a predicted temp. of a strip metal plate S at coiling timing calculated with a temp. prediction arithmetic part 41 from the detected results of a rolling speed sensor 10, plate thickness sensor 11, plate temp. sensor 12, coiling speed sensor 14 and present operation condition of a cooler 3 is given to a predicted temp. correction part 42, correction is executed based on deviation between the predicted temp. in past operation stored in a predicted error storage part 47 and the actual temp. In this case, the rolling speed of strip metal plate S detected by the rolling speed sensor 10 is stored in a speed storage part 46, by comparing the stored content to a prescribed reference speed, when both are largely different, a predicted error in this operation obtained from the actual tempt. detected by the coiling temp. sensor 13 is prohibited to be stored in the predicted error storage part 47, correction can not be executed with using this predicted error.