PURPOSE: To obtain a steel plate free from internal defcects by setting the rolling speed at the initial stage of rolling to a specified value or lower and setting the cumulative value of the product of an average surface pressure between a roll and a rolling material and a contacting time in roll biting to a prescribed value or higher.

CONSTITUTION: At each pass at the initial stage of rolling a thick plate; the rolling is performed by setting a rolling speed to ≤1m/sec, and setting the cumulative value of the product of an average surface pressure between a work roll and a rolling material, which is defined by a prescribed equation, and a contacting time (ti) in roll-biting, to ≥10. At each pass at the late stage after the rolling of initial stage, an ordinary rolling is performed. In this way, a thick plate free from internal defects is obtained by using a conventional rolling installation.