Abstract: The present invention discloses a sudden braking apparatus for a press comprising a driving motor (6), a flywheel (5) connected to the motor through a pulley (7) and a belt (8), a small gear (9) connected to the flywheel through a rotational shaft (3) installed horizontally to a supporting frame (2), a large gear (10) engaged with the small gear and installed on a crankshaft (11b) of the press, and a cam (14) mounted at the crankshaft (11a, 11b) and connected to a slide-block (12) via a crank rod (13), characterized in that the apparatus comprises a circular guide (19) slidably connected to the crankshaft (11b) and having a brake lining (16) on one side of the guide (19) facing the supporting frame (2), a radial toothed gear (18) on the other side of the guide and a tapered groove (15) extending from the circumference. In addition the apparatus includes a clutch plate (22) shifting device which enables the circular guide (19) to move horizontally.