A mass-balance means and a rotary microtome having the same are provided in the present disclosure. The mass-balance means includes: a connecting element, a first end of the connecting element being configured to be connected with a movable mass of the rotary microtome; a gear set having a preset gear ratio, a first end of the gear set being connected with a second end of the connecting element; an elastic element, the elastic element being pre-tensioned and adjustable, in which a first end of the elastic element is connected with a second end of the gear set for moving along with a rotation of the gear set so as to balance the movable mass.