A sealing cap includes an outer cap, an inner cap and an air-tight gasket. The outer cap is to be disposed on a container. The inner cap is movably connected beneath the outer cap. The air-tight gasket is sleeved around the inner and outer caps. Two connectors extend through the outer cap and are connected to the inner cap. An operator is disposed above the outer cap and is pivotally connected to the connectors. The operator is operable to move the inner cap relative to the outer cap between a pressurizing position, where the inner cap pressurizes the air-tight gasket against the container, and an unpressurizing position, where the inner cap unpressurizes the air-tight gasket against the container.