An optical fiber manufacturing method comprising: a drawing step of drawing an optical fiber by melting a leading end portion of an optical fiber preform; a resin-layer applying step of applying a resin onto the optical fiber in each of a plurality of successive holes included in a coating die by passing the optical fiber through the holes, to form a plurality of resin layers on an outer circumference of the optical fiber; and a coating-layer forming step of forming a plurality of coating layers by curing the resin layers, wherein the resin-layer applying step being characterized in that: supplying the resin to the coating die by a constant-rate pump while controlling a discharge amount of the constant-rate pump in such a manner that a pressure of supplying the resin to at least a hole for forming an innermost layer from among the holes becomes a predetermined value, calculating a difference between a setting value of a rotating speed of the constant-rate pump for obtaining a discharge amount that is determined according to the linear velocity of the optical fiber and an actual measurement value of the rotating speed of the constant-rate pump, controlling a thickness of each of the coating layers by controlling a temperature of the optical fiber when the optical fiber enters into the coating die, in accordance with a variation of the discharge amount of the constant-rate pump. a drawing step of drawing an optical fiber by melting a leading end portion of an optical fiber preform; a resin-layer applying step of applying a resin onto the optical fiber in each of a plurality of successive holes included in a coating die by passing the optical fiber through the holes, to form a plurality of resin layers on an outer circumference of the optical fiber; and a coating-layer forming step of forming a plurality of coating layers by curing the resin layers, wherein the resin-layer applying step being characterized in that: supplying the resin to the coating die by a constant-rate pump while controlling a discharge amount of the constant-rate pump in such a manner that a pressure of supplying the resin to at least a hole for forming an innermost layer from among the holes becomes a predetermined value, calculating a difference between a setting value of a rotating speed of the constant-rate pump for obtaining a discharge amount that is determined according to the linear velocity of the optical fiber and an actual measurement value of the rotating speed of the constant-rate pump, controlling a thickness of each of the coating layers by controlling a temperature of the optical fiber when the optical fiber enters into the coating die, in accordance with a variation of the discharge amount of the constant-rate pump. supplying the resin to the coating die by a constant-rate pump while controlling a discharge amount of the constant-rate pump in such a manner that a pressure of supplying the resin to at least a hole for forming an innermost layer from among the holes becomes a predetermined value, calculating a difference between a setting value of a rotating speed of the constant-rate pump for obtaining a discharge amount that is determined according to the linear velocity of the optical fiber and an actual measurement value of the rotating speed of the constant-rate pump, controlling a thickness of each of the coating layers by controlling a temperature of the optical fiber when the optical fiber enters into the coating die, in accordance with a variation of the discharge amount of the constant-rate pump.