To provide a standardized quick coupling easily operated even when the pressure of fluid is relatively high.

This quick coupling comprises two elements, or a male element B and a female element A adapted to be engaged with each other in the axial direction. For being engaged with the male element, the body 1 of the female element is provided with a load lock part attached for sliding in the body and penetrating through a central opening part. The wall of the opening part is formed with three teeth 53-55 mutually deviated along the central axis of the opening part. The male element is provided with a shoulder part 72 for selectively locking to one of the teeth. When the male element is locked with the intermediate tooth by its shoulder part, means allows a downstream pipe C2 to pass through an ambient air.