There is provided a crystalline TFT in which reliability comparable to or superior to a MOS transistor can be obtained and excellent characteristics can be obtained in both an on state and an off state. A gate electrode of the crystalline TFT is formed of a laminate structure of a first gate electrode made of a semiconductor material and a second gate electrode made of a metal material. An n-channel TFT includes an LDD region, and a region overlapping with the gate electrode and a region not overlapping with the gate electrode are provided, so that a high electric field in the vicinity of a drain is relieved, and at the same time, an increase of an off current is prevented.