A liquid crystal display device provided with a thin film transistor with excellent electrical characteristics and reduced off current, for which increase in manufacturing costs can be suppressed while suppressing reduction in yield. A thin film transistor includes a gate electrode provided over a substrate; a gate insulating film provided to cover the substrate and the gate electrode; a first island-shaped semiconductor layer and a second island-shaped semiconductor layer each formed as a stack of a microcrystalline semiconductor layer and a buffer layer with a depression on an upper surface thereof, over the gate electrode with the gate insulating film interposed therebetween; a conductive semiconductor layer; and a conductive layer provided on the conductive semiconductor layer. The conductive semiconductor layer is provided between the first island-shaped semiconductor layer and the second island-shaped semiconductor layer in contact with the gate insulating film.