A magnetic sensor is formed by a fluxgate sensor and by at least one Hall sensor integrated in a same integrated device, wherein the magnetic core of the fluxgate sensor is formed by a magnetic region that operates also as a concentrator for the Hall sensor. The magnetic region is manufactured in a post-machining stage on the metallization layers wherein the energizing coil and sensing coil of the fluxgate sensor are formed; the energizing and sensing coils are formed on a semiconductor substrate housing the conductive regions of the Hall sensor.