In this letter, a tunnel-induced injection field-effect transistor (TI-FET) is proposed and demonstrated. Compared with conventional tunneling field-effect transistor, by changing N-type drain into P-type and inserting a N-type pocket layer into the underlap region, off-state current is appreciably reduced, due to higher hole barrier induced by the inserted N-type pocket layer which can prevent hole leakage current from the drain. During the switching process, the gate controlled tunneling electrons from the source are trapped in the N-type pocket region and simultaneously decrease the hole barrier of the drain, which can increase hole injection current much more rapidly than the hole diffusing over a barrier directly controlled by a gate as in P-type metal-oxide-semiconductor field-effect transistor and thus ensure a very steep subthreshold slope. When the device is switched on, on-state current can be enhanced due to the dominant hole current diffusing from the drain, which is higher than pure tunneling current. Therefore, this TI-FET can obtain high on-current, low off-current, as well as steep subthreshold slope.