PURPOSE: To improve the cooling efficiency of optical fiber by providing rotating blades around the optical fiber heated and drawn, and moving the air cooled enough in the vicinity of the inner peripheral wall of casing to the optical fiber side in the center of casing by the revolution of the blades.

CONSTITUTION: The casing 32 which the optical fiber 14 heated and drawn is passed through and the cooling gas 33 is introduced into, supporting members 38... which is located in the inside of the casing 32 and is allowed to be freely rotatable around the optical fiber 14 in the casing 32, and blades 53... which are fixed to the supporting members 38... and move the gas 33 in the vicinity of the inner peripheral wall of the casing 32 to the side of the optical fiber 14 in the center of the casing 32 while the supporting members 38... are rotated are provided. The cooling means for cooling the gas 33 in the casing 32, such as a flow passage 35 for circulating cooling liquid 34, is preferably provided in the casing 32.