Abstract: A bottle cap with an air removing device consists of a cap unit and an air stopper combined together. The cap unit includes an upper cap portion, a lower cylindrical portion and a valve formed in an interior of both the upper cap portion and the lower cylindrical portion and having a capsule-shaped cavity for a stopper of the air stopper to fit and move up and down therein to stop an air hole in a bottom of the valve so that the air in a bottle fitted with this cap may be pumped out by an extra air pump fitted in an open cavity of the upper cap portion. After the air in the bottle is pumped out, then the air stopper is pushed down by the air pump again, keeping the cap firmly fixed on the mouth of the bottle in an almost vacuum condition, wherein the food therein may not deteriorate for a long time.