Disclosed is a transdermal drug delivery system for delivering medication through the skin, and an improved technology for a painless needleless drug delivery system which uses microjets of a drug solution having a microscale diameter to perform in vivo drug solution delivery without using a hypodermic needle for perforating a skin layer. The microjet drug delivery system provided by the present invention comprises: a pressure chamber which has a predetermined accommodating space and which has a sealed interior sealingly filled with water serving as a liquid for generating pressure a drug chamber which is arranged in the vicinity of the pressure chamber so as to accommodate a drug solution in a predetermined accommodating space thereof, and which has, on one side thereof, a micronozzle for jetting the drug solution to the outside in mircojets an elastic membrane interposed between the pressure chamber and the micro-drug chamber and a laser unit for emitting a laser beam onto the liquid for generating pressure stored in the pressure chamber so as to generate bubbles in the liquid in order to generate pressure. The laser unit of the present invention uses a laser beam having a lasing wavelength of 2.8 to 3.0 µm, in particular an erbium YAG (Er:YAG) laser having a wavelength of 2.94 µm (2940 nm).Linvention concerne un système de délivrance transdermique de médicament, servant à délivrer un médicament à travers la peau, ainsi quune technologie améliorée pour un système de délivrance de médicaments sans aiguilles indolore qui utilise des microjets dune solution médicamenteuse ayant un diamètre à échelle microscopique afin de permettre la délivrance dune solution médicamenteuse in vivo sans utiliser daiguille hypodermique pour percer une couche de la peau. Le système de délivrance de médicament à microjets selon la présente invention comprend : une chambre de pression qui possède un espace de réception prédéterminé ainsi quun intérieur fermé rempli hermétiquement deau ser
