A vacuum cleaner is disclosed. The present invention relates to a vacuum cleaner that is able to form dust and foreign substances collected in a dust collection device provided therein in a single mass shape to discharge it efficiently, not scattered in a dust collecting device. The vacuum cleaner includes a body, a dust collection device collecting dust and foreign substances therein, a compression device provided in the dust collection device to collect the dust and foreign substances collected in a predetermined portion of the dust collection device and to compress the collected dust and foreign substances, and a liquid supply device arranged in the dust collection device, in communication with an inside of the dust collection device, to supply liquid material to the dust collection device.