A device for automatic detection of states of motion and rest includes at least one inertial sensor, having at least one preferential detection axis, and a converter, which is coupled to the inertial sensor and supplies a first signal correlated to forces acting on the first inertial sensor according to the preferential detection axis; the device further includes at least one processing stage for processing the first signal, which supplies a second signal correlated to a dynamic component of the first signal, and at least one threshold comparator, which supplies a pulse when the second signal exceeds a pre-determined threshold.