PURPOSE: To obtain a strip having surely uniform and desired mechanical characteristic by actually measuring transformation rate of the strip, controlling the strip temp. in finish-rolling and starting γ→α transformation in the desired necessary time after completing the finish-rolling.

CONSTITUTION: The strip 11 is conveyed with table rollers 9a in a run-out table 9 through the hot finish-rolling and coiled to a down coiler 10. In the above hot rolling line, plural transformation rate sensors 2 are set along the line direction of run-out table 9. Based on the transformation rate measured with this, starting position of γ→α transformation is detected. Successively, the necessary time for arrival to the starting position of transformation from the completed time of finish-rolling is calculated with an operation processor 6. This necessary time is compared with the preset time, and a flow rate control valve 4 for cooling water is adjusted through a first and second proportional integral algorithms 7, 8 and a cooling device is controlled so that the above necessary time corresponds to the desired value. By this method, the product having uniform and desired mechanical characteristic is obtd., and this method can flexibly deal with speed variation in the rolling line, etc.