The present invention relates to a novel type of a needle-free drug delivery system in which strong energy such as a laser beam is focused inside liquid contained in a sealed pressure chamber to cause bubble growth and the volume expansion in the sealed pressure chamber due to the bubble growth so as to elongate an elastic membrane, so that an instantaneous pressure is applied to a drug solution contained in a drug microchamber adjacent to the elastic membrane to allow the drug solution to be injected in the form of a liquid microjet, thereby enabling the drug solution to rapidly and accurately penetrate into the bodily tissues of the patient.
