A manufacturing method of a solar cell including a transparent conductive film formed on a transparent substrate includes the steps of: preparing a target, the target including ZnO and a material including a substance including an Al or a Ga, the ZnO being a primary component of the target; in a first atmosphere including a process gas, applying a sputter electric voltage to the target and forming a first layer included in the transparent conductive film; in a second atmosphere including a greater amount of an oxygen gas compared to the first atmosphere, applying a sputter electric voltage to the target and forming a second layer on the first layer, the second layer being included in the transparent conductive film; and forming an irregular shape by performing an etching process on the transparent conductive film.