A drug ejecting apparatus has an ejection port and an element which generates energy for ejecting a drug from the ejection port a drug containing unit is connected to the drug ejection apparatus, and contains the drug a movable wall is attached to an end of the drug containing unit, and is displaced by difference between pressures inside and outside of the drug containing unit and a control unit displaces the movable wall. The drug ejection apparatus is filled with the drug, and the inside pressure of the drug containing unit is put in a negative pressure state in advance of ejecting of the drug, by displacing the movable wall by means of the control unit.
