The present invention provides a carbon nanotube which is purified through a method including the steps of: reacting metal remaining in a carbon nanotube with a chorine containing compound at a first temperature in a vacuum or inert atmosphere; chlorinating the remaining metal; and evaporating and removing the chlorinated remaining metal at a second temperature that is higher than the first temperature, wherein a carbon nanotube is provided that has an average value of an intensity ratio (IG/ID) of a G band and a D band, as measured through Raman spectroscopy, that is increased by 20% or more when compared to the carbon nanotube before purification.