In an integrated free-fall detection device for a portable apparatus an acceleration sensor generates acceleration signals correlated to the components of the acceleration of the portable apparatus along three detection axes. A dedicated purely hardware circuit connected to the acceleration sensor generates a free-fall detection signal in a continuous way and in real-time. The free-fall detection signal has a first logic value in the event that the acceleration signals are simultaneously lower than a respective acceleration threshold, and is sent to a processor unit of the portable apparatus as an interrupt signal to activate appropriate actions of protection for the portable apparatus. Preferably, the acceleration sensor and the dedicated purely hardware circuit are integrated in a single chip and the acceleration sensor is made as a MEMS.