A manufacturing method of a display device includes providing an image display layer on a first substrate comprising a first transmission area and a display area around the first transmission area, the pixel layer overlapping the display area, providing a second substrate facing the first substrate, the second substrate comprising a second transmission area overlapping the first transmission area, providing a transparent material between the first transmission area and the second transmission area, and melting each of a portion of the first transmission area adjacent to the transparent material, the transparent material, and a portion of the second transmission area adjacent to the transparent material to form a connection portion that connects the first transmission area and the second transmission area.