A device for detecting a shaft rupture in a rotor of a turbine, in particular a medium-pressure turbine, of a gas turbine, in particular of an aircraft engine, at least one stator-side sensor element being positioned downstream from the turbine, in particular in the area of a stator-side blade ring of another turbine, in particular a low-pressure turbine, and, in case of a shaft rupture of the rotor of the turbine, a radially externally situated segment of a last (seen in the direction of flow) rotor-side blade ring of the turbine working together with the, or with each, sensor element to generate an electrical signal corresponding to the shaft rupture.