A quick clamping device for a portable power tool includes at least one rotatably drivable output shaft, at least one clamping unit, at least one operating unit, and at least one uncoupling unit. The clamping unit, for tool-free fastening of an insert tool unit to the output shaft, includes at least one movably mounted clamping element for applying clamping force to the insert tool unit in a clamping position of the clamping element. The operating unit is configured to move the clamping element into the clamping position and/or into a release position of the clamping element. In the release position, the insert tool unit can be removed from the clamping unit. The at least one uncoupling unit is configured to uncouple the operating unit from the clamping unit in accordance with the rotational speed of the output shaft.