An optical fiber winding mechanism configured to feed an optical fiber from a raw material bobbin (B1, B2), around which the optical fiber is wound, toward a winding bobbin, the optical fiber winding mechanism comprising: a first raw material bobbin-side unit to mount a first raw material bobbin thereon; a second raw material bobbin-side unit to mount a second raw material bobbin thereon; and a controller to control each of the units, wherein the optical fiber winding mechanism is switchable between a first winding state in which the optical fiber of the first raw material bobbin is wound around the winding bobbin and a second winding state in which the optical fiber of the second raw material bobbin is wound around the winding bobbin, wherein in the first winding state, the winding bobbin is detached from the first raw material bobbin and is rotated with the second raw material bobbin, and in the second winding state, the winding bobbin is detached from the second raw material bobbin and is rotated with the first raw material bobbin, the first raw material bobbin-side unit comprises: a conveyance path forming mechanism that configures a conveyance path of the optical fiber set to head from the first raw material bobbin to the winding bobbin; characterised in that the first raw material bobbin-side unit further comprises: a dancer mechanism that is disposed in the conveyance path; and a tension measuring mechanism that is disposed on an upstream side of the dancer mechanism in the conveyance path, the tension measuring mechanism being configured to measure tension of the optical fiber, and in that the dancer mechanism comprises: a dancer roller that is disposed to be movable linearly in a vertical direction; and a dancer-side urging member that supports the dancer roller from above the dancer roller and urges the dancer roller in the vertical direction. a first raw material bobbin-side unit to mount a first raw material bobbin thereon; a second raw material bobbin-side unit to mount a second raw material bobbin thereon; and a controller to control each of the units, wherein the optical fiber winding mechanism is switchable between a first winding state in which the optical fiber of the first raw material bobbin is wound around the winding bobbin and a second winding state in which the optical fiber of the second raw material bobbin is wound around the winding bobbin, wherein in the first winding state, the winding bobbin is detached from the first raw material bobbin and is rotated with the second raw material bobbin, and in the second winding state, the winding bobbin is detached from the second raw material bobbin and is rotated with the first raw material bobbin, the first raw material bobbin-side unit comprises: a conveyance path forming mechanism that configures a conveyance path of the optical fiber set to head from the first raw material bobbin to the winding bobbin; a dancer mechanism that is disposed in the conveyance path; and a tension measuring mechanism that is disposed on an upstream side of the dancer mechanism in the conveyance path, the tension measuring mechanism being configured to measure tension of the optical fiber, and in that the dancer mechanism comprises: a dancer roller that is disposed to be movable linearly in a vertical direction; and a dancer-side urging member that supports the dancer roller from above the dancer roller and urges the dancer roller in the vertical direction.