A sealed medication dispensing and administering device has a syringe, a plunger, a connecting holder, an elastic valve, and a liquid stopper. The syringe has an outer barrel having an air inlet tube and an inner barrel inserted inside the outer barrel and having a medication inlet tube. The plunger is inserted within the outer and inner barrels. The connecting holder is connected to the syringe and has a connecting cover with at least one outer connecting hole and two piercing needles respectively piercing inside the air inlet tube and the medication inlet tube. Inner spaces of the two piercing needles communicate with the at least one outer connecting hole. The elastic valve selectively covers the two piercing needles. The fluid stopper is disposed within the connecting cover and blocks one of the at least one outer connecting hole and the inner space of the air inlet tube.
