In view of the problem that a reduced thickness of an EL film causes a short circuit between an anode and a cathode and malfunction of a transistor, the invention provides a display device that has a light emitting element including an electrode and an electroluminescent layer, a wire electrically connected to the electrode of the light emitting element, a transistor provided with an active layer including a source, a drain and a channel forming region, and a power supply line electrically connected to one of the source and the drain of the transistor, wherein the wire is electrically connected to the other of the source and the drain of the transistor, and the width of a part of the electrode in the vicinity of a portion where the electrode is electrically connected to the wire is smaller than that of the electrode in the other portion.