The invention relates to an implantable capsule, particularly an autonomous capsule of cardiac stimulation, including a tubular body provided at the distal end of an anchoring element with a helical screw adapted to penetrate tissue a wall of an organ of a patient, the body housing a set of functional elements of the capsule. It includes, in an annular area surrounding the base of the screw recessed arrangements defining a set of flush tips oriented in a circumferential direction opposite to that of the screwing, to avoid the unscrewing of the capsule.
