Provided is a method of electrophoresis of carbon nanotube for separating them into metallic carbon nanotubes and semiconducting carbon nanotubes, and the method comprises a step of electrifying a carbon nanotube sealed gel in which carbon nanotubes are dispersed in a gel.According to the separation method, metallic CNT and semiconducting CNT may be efficiently and heavily separated and purified from each other in CNT containing both the two within a short period of time and in a simplified manner by the use of inexpensive facilities and according to a simple process, and the method can be readily scaled up, in which CNT can be separated industrially extremely advantageously.