<p>The invention relates to a device for bleeding a hydraulic system. The bleeding device comprises a venting passage which can be closed by means of a valve arrangement. In order to simplify such a bleeding device regarding the operation thereof while preventing air from being delivered in an uncontrolled manner during the bleeding process, the valve arrangement is provided with a valve member (S) which can be lifted from a valve seat (8) of the valve arrangement counter to the force of a spring element (7) in an open position of the bleeding device while being fixed to the valve seat (8) in a closed position of the bleeding device. The invention further relates to a venting screw which encompasses such a valve arrangement according to the principle of a check valve and is to be mounted in a caliper (18).</p>