It is an object of the present invention to provide a semiconductor device including a wiring having a preferable shape. A manufacturing method includes the steps of forming a first conductive layer connected to an element and a second conductive layer thereover; forming a resist mask over the second conductive layer; processing the second conductive layer by dry etching with the use of the mask; and processing the first conductive layer by wet etching with the mask left, wherein the etching rate of the second conductive layer is higher than that of the first conductive layer in the dry etching, and wherein the etching rate of the second conductive layer is the same as or more than that of the first conductive layer in the wet etching.