A quick clamping device for a portable machine tool includes at least one drive shaft, at least one clamping unit, and at least one operating unit. The clamping unit has, for tool-less fastening of an insertion tool on the drive shaft, at least one clamping element for exerting a clamping force on the insertion tool in a clamping position. The operating unit is configured to move the clamping element into a release position, and includes at least one operating element, in particular an operating lever. The operating element has at least one activation surface for movement of the clamping element into the release position. The activation surface is arranged such that at least one force initiation point of the operating element is movable, upon interaction with a contact surface of an actuating element of the operating unit, as a factor of movement of the operating element on the contact surface.