A worktable including an opening and an upper surface for supporting a workpiece; a supporting unit for supporting the worktable; a cutting mechanism mounted on a lower surface of the worktable and contained within the supporting unit including: a motor for outputting a rotation motion; a reciprocating rod driving a saw blade moving reciprocately through the opening; a motion conversion mechanism converting the rotation motion of the motor into a reciprocating motion of the reciprocating rod; and a saw blade clamp for clamping and releasing the saw blade; the saw blade clamp including an operating element which is disposed on the external surface of the worktable or the supporting unit.