To provide a display device which can be manufactured with higher efficiency in the use of material through a simplified manufacturing process, and a method for manufacturing the display device. Another object is to provide a technique by which patterns of a wiring the like which constitutes the display device can be formed to a desired shape with good control. In a method for forming a pattern according to the present invention, a mask is formed over a light-transmitting substrate; a first region including a photocatalyst is formed over the substrate and the mask; the photocatalyst is irradiated with light through the substrate to modify a part of the first region; a second region is formed; and a composition containing a pattern forming material is discharged to the second region, thus, a pattern is formed. The mask does not transmit light.