An autonomous intracorporeal capsule including a body and, inside this body, electronic circuits and an energy harvesting module for the power supply of these electronic circuits, the energy harvesting module comprising a transducer adapted to convert into electric energy a cyclic external physical stress applied to the capsule body and resulting from pressure variations in the medium surrounding the capsule and/or from movements of a wall to which the capsule is anchored, wherein the energy harvesting module comprises: - a primary oscillating structure subjected to said external cyclic stress, this primary oscillating structure being adapted to be alternately moved in one direction and in the other at the frequency of said external cyclic stress; - a secondary oscillating structure non subjected to said cyclic external stress, this secondary oscillating structure comprising a deformable elastic element and being adapted to vibrate freely at a self-resonant frequency higher than said frequency of the external cyclic stress; and - an electrostatic structure comprising a first capacitor electrode and a second capacitor electrode coupled to the secondary oscillating structure, wherein the first and the second electrode are configured between each other so that, under the effect of said external cyclic stress applied to the primary oscillating structure, they exert between each other, under the effect of electrostatic interactions, a force of mutual attraction driving the secondary oscillating structure away from its stable equilibrium position and with tensioning of the deformable elastic element, the secondary oscillating structure being hence driven to a limit where the tension exerted by the deformable elastic element exceeds the force of mutual attraction of the electrodes, limit beyond which the secondary oscillating structure is released by a relaxation effect to vibrate freely at said self-resonant frequency, and wherein the transducer is coupled to the secondary oscillating structure, to convert into electric energy the movements of vibration of the latter at said self-resonant frequency, characterized in that: - the primary oscillating structure and the secondary oscillating structure are coupled to each other by said deformable elastic element; and - the first electrode of the electrostatic structure is connected to the body of the capsule. - a primary oscillating structure subjected to said external cyclic stress, this primary oscillating structure being adapted to be alternately moved in one direction and in the other at the frequency of said external cyclic stress; - a secondary oscillating structure non subjected to said cyclic external stress, this secondary oscillating structure comprising a deformable elastic element and being adapted to vibrate freely at a self-resonant frequency higher than said frequency of the external cyclic stress; and - an electrostatic structure comprising a first capacitor electrode and a second capacitor electrode coupled to the secondary oscillating structure, - the primary oscillating structure and the secondary oscillating structure are coupled to each other by said deformable elastic element; and - the first electrode of the electrostatic structure is connected to the body of the capsule.