According to one embodiment, provided is a thin film transistor with which it is possible to reduce the leakage current and thereby, for a liquid crystal display device, to ensure a good display quality. The thin film transistor includes a semiconductor layer, gate electrodes, first light-blocking electrodes, and second light-blocking electrodes. The first light-blocking electrodes are disposed opposite to the gate electrodes with respect to the semiconductor layer and opposed to channel regions to block light incident into the channel regions. The second light-blocking electrodes are disposed opposite to the semiconductor layer with respect to the gate electrodes, arranged to block light incident into the channel regions, and electrically connected with one of a signal line and a pixel electrode.