An apparatus of producing quantum dots, comprising: at least one pump (10-1, 10-2) to inject a plurality of precursor solutions in which different kinds of precursors are dissolved; a mixer to mix the plurality of precursor solutions; and: a) a plurality of heating furnaces (14, 16) to pass the mixture solution therethrough under different temperature conditions, wherein the plurality of heating furnaces (14, 16) includes a first heating furnace to provide a first temperature condition for nucleation, and a second heating furnace to provide a second temperature condition for nuclear growth, characterized by a buffer disposed between the first heating furnace and the second heating furnace and passing the mixture solution through the buffer which is under a third temperature condition that is temperature lower than that of the first and second temperature conditions, or b) a heating furnace providing a first heating area that is under a first temperature condition and a second heating area that is under a second temperature condition, wherein the first heating area A maintains a higher temperature than the second heating area B, characterized by a buffer area provided between the first and second heating areas (A, B) in the heating furnace, wherein buffer area maintains a lower temperature than heating areas (A and B). at least one pump (10-1, 10-2) to inject a plurality of precursor solutions in which different kinds of precursors are dissolved; a mixer to mix the plurality of precursor solutions; and: a) a plurality of heating furnaces (14, 16) to pass the mixture solution therethrough under different temperature conditions, wherein the plurality of heating furnaces (14, 16) includes a first heating furnace to provide a first temperature condition for nucleation, and a second heating furnace to provide a second temperature condition for nuclear growth, characterized by a buffer disposed between the first heating furnace and the second heating furnace and passing the mixture solution through the buffer which is under a third temperature condition that is temperature lower than that of the first and second temperature conditions, or b) a heating furnace providing a first heating area that is under a first temperature condition and a second heating area that is under a second temperature condition, wherein the first heating area A maintains a higher temperature than the second heating area B, characterized by a buffer area provided between the first and second heating areas (A, B) in the heating furnace, wherein buffer area maintains a lower temperature than heating areas (A and B). a) a plurality of heating furnaces (14, 16) to pass the mixture solution therethrough under different temperature conditions, wherein the plurality of heating furnaces (14, 16) includes a first heating furnace to provide a first temperature condition for nucleation, and a second heating furnace to provide a second temperature condition for nuclear growth, characterized by a buffer disposed between the first heating furnace and the second heating furnace and passing the mixture solution through the buffer which is under a third temperature condition that is temperature lower than that of the first and second temperature conditions, or b) a heating furnace providing a first heating area that is under a first temperature condition and a second heating area that is under a second temperature condition, wherein the first heating area A maintains a higher temperature than the second heating area B, characterized by a buffer area provided between the first and second heating areas (A, B) in the heating furnace, wherein buffer area maintains a lower temperature than heating areas (A and B).