Abstract: There is provided hydraulically-operated work roll gap control cylinders forming a closed-circuit hydraulic system during rolling, and there are also provided hydraulically-operated backup roll control cylinders to which is connected a rolled product thickness gauge in order to keep constant the work roll gap depending on the pressure existing in the closed-circuit hydraulic system. The apparatus is provided with a hydraulic volume compensator operating in conjunction with the closed-circuit hydraulic system of work roll gap control and is also provided with a logic module connected to said compensator. The volume of fluid contained in the closed-circuit system changes in response to the corrective signal characteristic of a deviation of the strip thickness from the specified gauge. The passage of the signal to the hydraulic volume compensator is cleared or blocked by a special transportation lag unit.