Since a film, which is the upper layer of an interlayer insulating film and has a fast etching rate, does not have dense film quality, moisture is entered from the end portion of a substrate, and it is likely that display unevenness and the like occur. A manufacturing method of a display device includes the steps of: forming a first contact hole on the first interlayer film; forming a second interlayer film on the first interlayer film and in the first contact hole, the second interlayer film having a lower layer film and an upper layer film having an etching rate faster than an etching rate of the lower layer film; forming a second contact hole on the second interlayer film; and removing at least a part of the upper layer film.