To provide a nip pressure control method of a coater head of a roll coater by which control parameters are renewed to enable nip pressure control which is stable and has good responsiveness, not by manual operation even if a roll is replaced or roll hardness undergoes secular change.

In a nip pressure control method in a coater head of a roll coater by which nip pressure control between a roll to be controlled and a reference roll is performed by back and forth movement of the roll to be controlled based on a deviation of from a nip pressure set value to a nip pressure measured value moving average value, during nip pressure control, the difference of the maximum and the minimum of a nip pressure measured value is calculated at intervals of fixed time, and also based on a nip pressure variation which the difference calculated one after one is subjected to a moving average process to obtain, a dead zone set value of the nip pressure control is periodically renewed.