PURPOSE: To form a coating film with uniform film thickness by standing a cylindrical or columnar shaft body in a dipping tank and inserting this shaft body into a cylindrical body.

CONSTITUTION: The upper end part of a drum 14 is held by a holding means 17 and closed, and while the drum 14 is lowered gradually to insert the shaft body 12 into the drum 14, the drum 14 is dipped in coating liquid 15. At this time, air flows in and out through an air pressure control valve 13 and thus control is so performed that the atmospheric pressure on the lower end surface of the drum 14 is nearly equal to the hydraulic pressure of the depth. Consequently, the coating liquid 15 is prevented from entering the drum 14 and the air in the drum 14 is prevented from flowing out as air bubbles. Further, the shaft body 12 is stood previously in the dipping tank 11 and while this shaft body 12 is inserted, the drum 14 is dipped, so the volume reduced by the dipping of the drum 14 is reduced to reduce up-down fluctuations of the liquid level of the coating liquid 15 due to up-down movement of the drum 14. Consequently, the outer peripheral surface of the drum 14 is coated with the coating liquid 15 to uniform thickness.