A surgical thread cutter (10) has a blade (18) movable via an actuation mechanism (30) relative to an anvil (20) toward and away from the latter, and a spring by way of which the blade (18) can be acted upon by spring force in one movement direction. In the interest of better and safer handling, it is proposed that the spring act upon the blade (18) in the cutting direction, that a retention system be provided by means of which the blade (18) can be locked in a position remote from the anvil (20); and that the force of the spring be set in such a way that after the retention system is released, the blade (18) can be moved onto the anvil (20) in the manner of a guillotine (FIG. 1).