A radial torque limiter, for example, for a geared rotary actuator (1, 1') including input member (S, 8) coupled to an output member (3 or 3') driving a sun gear (4) and planet gears (5) through axially projecting tabs (3g). Roller elements (2) are arranged at ramp sections (3a, 3b, 3c, 3d, 8a, 8b, 8c, 8d) formed at the input member (S, 8) and output member (3 or 3') for radially outwardly displacing the beam spring portions of the output member (3 or 3') to radially apply braking force between an external surface (14) of the beam springs and an internal surface (13) of a grounded reaction member (12) so as to brake the input member (S, 8) and output member (3 or 3') upon an occurrence of an excess transmitted torque.