Abstract: A pressure detecting unit detects a pressure of supplying a resin to at least a hole for forming an innermost resin layer on an optical fiber from among a plurality of successive holes in a coating die. A control unit controls a discharge amount of a constant-rate pump that supplies the resin to the coating die in such a manner that a detected resin pressure becomes a predetermined value, and controls a temperature of the optical fiber so that the temperature of the optical fiber becomes a predetermined temperature in accordance with a variation of the discharge amount of the constant-rate pump.