A magnetic bearing, adapted to equip a rotary apparatus. The magnetic bearing comprises: an actuator sub-assembly provided with a magnetic base and at least three actuator bobbins mounted on the magnetic base, and a sensor sub-assembly provided with at least three magnetic sensors associated with the actuator bobbins. At least one sub-assembly amidst the actuator sub-assembly and the sensor sub-assembly comprises at least three sectors mounted together. Each sector includes at least one actuator bobbin when the sector belongs to the actuator sub-assembly, or at least one magnetic sensor when the sector belongs to the sensor sub-assembly. The invention also concerns a rotary apparatus comprising such a magnetic bearing and a method for manufacturing such a magnetic bearing.