To coat an object to be coated without coating unevenness by removing not only foams generated when a coating material is squeezed from a pick-up roll and dropped on the coating material surface but also foams generated in a supply part of the coating material to a coating material pan.

The coating material pan 7 for a roll coater comprises a coating material storage tank 8 for storing a coating material 22 and a coating material overflowing tank 9 for receiving the coating material overflowing out of the coating material storage tank. Movable partitions moving up and down independently in the right and left width direction of the long side are formed in the long side faces opposed to each other of the coating material storage tank and at the same time the coating material overflowing tank is installed in the surrounding of the coating material storage tank so as to surround the coating material storage tank and a coating material in an amount equal to or more than the amount to be applied to the object to be coated is supplied to the coating material storage tank and the excess amount of the coating material is made to overflow constantly from the entire body of the upper end part of the movable partitions by adjusting the height positions of the upper ends of the movable partitions.