Fuel injector for an internal combustion engine, comprising: an injection nozzle with a body in which a needle is arranged that can be moved between a closed position (PF), in which a first end of the needle rests on a seat and closes off injection orifices of the nozzle, and a fully open position (PO), in which the first end of the needle is lifted from its seat and allows injection; a control chamber that is filled, in operation, with fuel so as to exert a pressure on the second end of the needle; a control valve associated with the control chamber that allows the fuel pressure in the control chamber to be selectively varied and thus allows an opening or closing movement of the needle to be controlled, the control valve being driven by an actuator; a device for detecting the position of the needle; the device for detecting the position of the needle includes an elastic element of contact that extends in the control chamber and is able to follow the movement of the needle so as to adopt two positions in which it closes a detection circuit, said two positions corresponding respectively to the closed (PF) and fully open (PO) positions of the needle characterized in that the element of contact comprises a base part that is mounted so as to be fixed and electrically insulated, and an elastically flexible contact part that extends in the control chamber and is at a predetermined electric potential, the contact part bearing on the end part of the needle, while being electrically insulated therefrom; when the needle is in the closed position (PF), the element of contact closes the detection circuit by contact of the contact part with a first point of contact in the peripheral region of the control chamber ; and when the needle is in the open position (PO), the element of contact closes the detection circuit by contact of the contact part with a second point of contact in the region of the ceiling of the control chamber . an injection nozzle with a body in which a needle is arranged that can be moved between a closed position (PF), in which a first end of the needle rests on a seat and closes off injection orifices of the nozzle, and a fully open position (PO), in which the first end of the needle is lifted from its seat and allows injection; a control chamber that is filled, in operation, with fuel so as to exert a pressure on the second end of the needle; a control valve associated with the control chamber that allows the fuel pressure in the control chamber to be selectively varied and thus allows an opening or closing movement of the needle to be controlled, the control valve being driven by an actuator; a device for detecting the position of the needle; the device for detecting the position of the needle includes an elastic element of contact that extends in the control chamber and is able to follow the movement of the needle so as to adopt two positions in which it closes a detection circuit, said two positions corresponding respectively to the closed (PF) and fully open (PO) positions of the needle characterized in that the element of contact comprises a base part that is mounted so as to be fixed and electrically insulated, and an elastically flexible contact part that extends in the control chamber and is at a predetermined electric potential, the contact part bearing on the end part of the needle, while being electrically insulated therefrom; when the needle is in the closed position (PF), the element of contact closes the detection circuit by contact of the contact part with a first point of contact in the peripheral region of the control chamber ; and when the needle is in the open position (PO), the element of contact closes the detection circuit by contact of the contact part with a second point of contact in the region of the ceiling of the control chamber . <EOS>