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 separation device mounted in the body, a dust collection device independently provided from the dust separation device, connected to the dust collection device, a compression device provided in the dust collection device, to collect 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 provided in the dust separation device to supply liquid material to the dust separation device.