A waterproof electromagnetic device and production method thereof, the waterproof electromagnetic device comprising a magnetic core (10) surrounded by at least one coil (20); an electronic circuit board (30) including at least connection pins (31) electrically connected to the at least one coil (20); and an enclosure (40) overmolded on a waterproof manner surrounding the magnetic core (10), the at least one coil (20) and the electronic circuit board (30); wherein the magnetic core (10) further includes several protrusions (11) projecting from the magnetic core (10) towards an external surface of the enclosure (40), so that a centering of the magnetic core (10) within the enclosure (40) is provided during the overmoulding operation.