A spinning machine includes: a main shaft which includes a chuck holding a cylindrical material having a bottom and a regulation member; a mandrel which is inserted inside from an opening side end portion of the material; and a press roller which presses the opening side end portion of the material. The spinning machine molds a circumferential groove portion on the opening side end portion so that an inner diameter of the opening side end portion of the material is smaller than an inner diameter of a body of the material by pushing a press roller while rotating the material around the axial center of the main shaft, and at least a portion of the inserted mandrel is formed so that a gap is provided between the portion and an inner circumferential surface after the opening side end portion of the material is plastically deformed.