In a method of manufacturing a three-dimensional (3D) circuit device, conducting circuits are formed on a non-conductive base through electroplating. The non-conductive base, and a circuit pattern section, at least one conducting junction and at least one current-guiding junction provided on the base are formed through double injection molding process. An electrically conductive interface layer is formed on the circuit pattern section and the junctions; and then, metal circuits are formed on the circuit pattern section through electroplating. By providing the conducting junction and the current-guiding junction, when forming metal circuits through electroplating, electroplating current can be evenly distributed over the circuit pattern section to form metal coating with uniform thickness, which enables upgraded production efficiency and reduced cost in manufacturing a 3D circuit device.