The invention relates to a vacuum cleaner with a dirt collection tank which has a suction inlet and is in flow connection with at least one suction unit via at least one filter and at least one extraction line, and with at least one external air inlet which opens into the extraction line downstream of the filter and can be closed by means of at least one closing valve, wherein the closing valve has a movable valve member which is acted upon by a spring-elastic restoring device with a closing force and in the closing position, in addition, by a magnetic holding device with a magnetic holding force. In order to develop the vacuum cleaner further in such a manner that it makes a particularly effective cleaning of the filter possible, it is suggested in accordance with the invention that the magnetic holding device have an electromagnet which can be acted upon with an exciting current for the purpose of closing the closing valve and that the valve member can be moved continuously back into the closing position via the open position, proceeding from the closing position, when the exciting current is interrupted, wherein the switch-off time of the exciting current is adapted to the movement time of the valve member.