A touch screen panel includes a substrate, sensing electrodes, outer wirings, contact units, and at least one dummy pattern. The substrate includes an active region and a non-active region, the non-active region disposed outside the active region. The sensing electrodes are disposed in the active region. The outer wirings are disposed in the non-active region. Each of the outer wirings is connected to a respective group of the sensing electrodes. The contact units connect the respective groups of sensing electrodes to the outer wirings. The at least one dummy pattern is disposed between adjacent contact units of the contact units.