A manufacturing method of a display device includes: forming a thin film transistor on a substrate, forming a pixel electrode connected to the thin film transistor, and forming a common electrode insulated from the pixel electrode. At least one of forming the pixel electrode and forming the common electrode includes: forming an electrode layer on the substrate, coating a photoresist on the electrode layer to form a first electrode sub-layer on which the photoresist is coated and a second electrode sub-layer on which the photoresist is not coated, generating etching vapor by heating an etching solution in a double boiler, and etching the second electrode sub-layer by using the etching vapor.