A sharpener is provided. The sharpener includes a clamping component, a sharpening seat, a sharpener holder, an arm body, a bearing ring, and a driving component, the clamping component is provided with a first rotating axis and a pair of mirrored clamping arms; one end of the arm body is sleeved on a horizontal rod, and the other end thereof is fixed to the first rotating axis; the bearing ring is sleeved on the arm body, a connecting ear is provided on an outer circumference of the bearing ring. When the driving component pushes the bearing ring to move along the arm body, the two clamping arms are caused to synchronously open and close to clamp or release a cutting tool. This sharpener combines low torque clamping and angle reproduction stability. Thus, it is suitable for precision grinding of various types of cutting tools.