A method and apparatus for fabricating an emitter by colliding an arc with the surface of a wafer inside a vacuum chamber are provided. The apparatus includes: a vacuum chamber in which a wafer is inserted; a magnetic field generating unit for generating a uniform magnetic field inside the vacuum chamber; an electric field generating unit for forming an electric field parallel to the magnetic field inside the vacuum chamber; and a master emitter for emitting electrons towards the wafer. The electrons emitted from the master emitter move along the magnetic field and the electric field. The arc is generated when the electric field or the driving voltage surpasses a threshold by controlling the strength of the electric field and the driving voltage of the master emitter. Thus, the surface of the wafer is instantaneously melted and solidified by the arc, thereby forming the emitter with a sharp tip on the surface of the wafer.