A liquid crystal display device having a high definition screen in which a pixel electrode is formed in a region surrounded by a gate line and a drain line, and a trapezoidal protrusion having an upper surface and inclined surfaces is formed below the gate line. Since a TFT is formed over a trapezoidal protrusion and a channel portion is formed over the upper surface and the inclined surfaces of the trapezoidal protrusion, the width of the channel portion can be enlarged compared to that of a channel portion formed over a plane. The pixel electrode is in contact with a source electrode at the inclined surface of the trapezoidal protrusion. This configuration allows the TFT and a contact of the pixel electrode and a source electrode to be formed over part of the trapezoidal protrusion.