A display device includes a base substrate in which a display area and a pad area disposed around the display area are defined, a plurality of panel pads disposed on the pad area of the base substrate, and a printed circuit board attached to the pad area of the base substrate. The printed circuit board includes a plurality of circuit pads, the plurality of circuit pads include a first lead align mark, and the first lead align mark includes a plurality of first patterns passing through the first lead align mark from a surface of the first lead align mark in a thickness direction.