A vibrator for a bone conduction type hearing aid device. The vibrator includes a coil for generating a dynamic magnetic field and two permanent magnets for generating a static magnetic field. The two permanent magnets are working independently from each other in the magnetic circuit and an arranged in such a way that the static and dynamic magnetic fields are substantially separated from each other, but coinciding in the air gaps formed between the coil and magnet arrangement and the casing, whereby the vibrator provides an axial force.