The invention relates to a fuel injector for injecting two liquid and/or gaseous fuels with an injector housing (1), comprising a nozzle body (2) and a valve body (3). A first nozzle needle (7), arranged such that it can move in a stroke-like manner, is arranged in said injector housing (1) for opening and closing an injection cross-section (27). The first nozzle needle (7) is thereby designed as a hollow needle in which a second nozzle needle (8), arranged such that it can move in a stroke-like manner, is arranged. Same cooperates with an inner nozzle seat (25) formed in the first nozzle needle (7) to open and close at least one injection opening (35). The first nozzle needle (7) and the second nozzle needle (8) border an injection chamber (20) that can be filled with fuel via a supply throttle (36). In addition, in an upper switch position, the second nozzle needle (8) is in contact with a seal seat (38) and thereby separates a connection between the injection chamber (20) and the supply throttle (36).