An optical fiber apparatus and manufacturing method thereof includes: forming a bare optical fiber by melting and deforming an optical fiber preform; cooling the bare optical fiber after the bare optical fiber forming step by passing it through a flow channel of a cooling unit through which cooling gas flows; and forming a protective coating layer by supplying a molten resin to a periphery of the bare optical fiber after the cooling step thereby forming an optical fiber. The cooling gas flowing toward a vertically lower end of the flow channel is blocked by the molten resin used to form the protective coating layer, and carbon dioxide gas is supplied toward the flow channel from a position which is vertically below the supply position of the cooling gas and vertically above the blocking position of the molten resin.