A display device having a sensing unit includes a first substrate having a plurality of test spacers, and a second substrate having a plurality of sensing unit test lines facing the test spacers, respectively. The surface heights of the sensing unit test lines are different from each other. The heights of the test spacers are substantially the same. The second substrate further includes a plurality of height difference portions formed under the sensing unit test lines, and the number of height difference portions formed under the sensing unit test lines is different for different sensing unit test lines.