In an apparatus and method of generating a carbon nanotube (CNT), a process chamber is heated to a target temperature and a catalyst powder is supplied into the heated process chamber. The catalyst powder moves in a first direction in the process chamber. A source gas is supplied into the process chamber in a second direction opposite to the first direction, so that the source gas delays the movement of the catalyst powder in the first direction and is reacted with the catalyst powder in the process chamber to thereby produce the CNT in the process chamber. Accordingly, the flow of the source gas against the flow of the catalyst powder reduces the drop velocity of the catalyst powder. Therefore, the source gas and the catalyst powder may be reacted with each other for a sufficiently long time.