In the case of a tool clamping device, in particular, for an operating spindle of a processing machine, with an activation element (3) that can be moved by a drive between a first position, in which the tool clamping device is located in a clamped position, and a second position, in which the tool clamping device is located in a released position, a sensor is present in the form of at least one electrical component for detecting a position of the activation element (3). The sensor is integrated structurally into the tool clamping device and at least one section of the activation element (3) directly forms a component of the one or more electrical components, wherein its position influences an electrical property of this component. The component can be an electrical switch whose closed state depends on the position of the activation element (3) in that at least one section of the activation element (3) is electrically conductive and forms a contact electrode of the switch or a part of such an electrode. However, it could also be a capacitor or an inductor.