This device comprises a generator producing bursts (Si) of N pulses (I) of VNS stimulation generated in succession during respective periods of activity (TON) separated by intermediate periods of inactivity (TOFF) during which no stimulation is issued. Stochastic modulation circuitry controls the delivery of the bursts of each of the N pulses of each VNS burst by selective inhibition or not, of the generation of each of the VNS pulses depending on the result of a respective randomization. The number of VNS pulses of each burst is thus randomly varying, and thus the VNS stimulation energy of this burst and the interval between successive pulses, which counteract the appearance of a physiological compensation loop.