A device is provided for regulating the thickness of rolling stock in a roller stand. The device includes a control device that controls the roller adjustment of the roller stand as a function of the deviation between a reference thickness value (h*) and an estimated value (h') for the thickness of the rolling stock exiting from the roller stand; a model simulating the rolling process in the roller stand, the model calculating the estimated value (h') on the basis of roller technology parameters and measured values; a thickness measurement device that measures the thickness of the rolling stock after its exit from the roller stand with a measurement delay (T.sub.L) providing a measured thickness value (h.sub.L); a delay device for delaying the estimated value (h') determined by the model by at least approximately the amount of the measurement delay (T.sub.L); a correction device generating a correction value (k) as a function of a deviation (.DELTA.h.sub.L) between the measured thickness value (h.sub.L) and a delayed estimated value (h'.sub.L), the correction value (k) correcting the estimated value (h') provided by the model; a controllable switching device enabling the generation of the correction value (k) to be stopped in time periods during which the thickness measurement device provides no measured thickness values (h.sub.L) or no usable measured thickness values; and a holding device making available during the time periods the correction value (k) last generated for correction of the estimated value (h') provided by the model prior to the generation of the correction value (k) being stopped.