A magnetic tunnel junction (MTJ) device includes at least one magnetic tunnel junction element, silicon nitride spacers and tantalum containing spacers. The magnetic tunnel junction element is disposed on a dielectric layer, wherein a corresponding metal line is disposed in the dielectric layer contacting to the magnetic tunnel junction element. The silicon nitride spacers are disposed on sidewalls of the magnetic tunnel junction element. The tantalum containing spacers are disposed on sidewalls of the silicon nitride spacers, wherein at least one of the tantalum containing spacers includes a top part covering a part of a top surface of the magnetic tunnel junction element. The present invention also provides a method of manufacturing said magnetic tunnel junction (MTJ) device.