Abstract: A vacuum apparatus for easily forming a vacuum in any bottle, container or the like and for providing a stable sealing. A lower cylindrical member together with a disc member forms a space portion in which a vacuum or an atmospheric pressure is applied, and the lower portion of an upper cylindrical member is inserted in the space portion and divides the space portion into upper and lower spaces. With a downward movement of the upper cylindrical member, the upper space expands and draws air inside of a bottle, and with an upward movement thereof, the air introduced into the upper space is vented outside. At this time, a check valve is selectively opened and closed and is operated by a pressure difference applied thereon. By repetitive reciprocating movement of the upper cylindrical member, a high vacuum is formed in the bottle and is sealed by the check valve. The apparatus is adaptable in a vacuum bottle, a medical suction instrument or the like.