It is an object of the present invention to form a pixel electrode and a metal film using one resist mask in manufacturing a stacked structure by forming the metal film over the pixel electrode. A conductive film to be a pixel electrode and a metal film are stacked. A resist pattern having a thick region and a region thinner than the thick region is formed over the metal film using an exposure mask having a semi light-transmitting portion. The pixel electrode, and the metal film formed over part of the pixel electrode to be in contact therewith are formed using the resist pattern. Accordingly, a pixel electrode and a metal film can be formed using one resist mask.