The present invention provides a needleless syringe for injecting a substance for injection at an injection region on a body without the intermediary of an injection needle. The needleless syringe comprises: a syringe body a housing part for housing the substance for injection, with a sealing member interposed, in a housing compartment provided in the syringe body a compression part which moves or breaks the sealing member by compressing the substance for injection which is housed in the housing part, whereby the substance for injection is ejected to the outside a flow path part which defines a flow path in such a way that an ejection opening to the injection region is formed and the substance for injection which has been compressed by the compression part is ejected through the ejection opening at the injection region and an advance filling part which allows the flow path part to be filled with some of the substance for injection inside a housing chamber by breaking of part of the sealing member, before pressure has been applied by the compression part. As a result, it is possible to reduce the load on a nozzle and reduce the noise when an injection is made, without impairing the ease with which a user can use the needleless syringe.La présente invention porte sur une seringue sans aiguille pour linjection dune substance à injecter au niveau dune région dinjection sur un corps sans lintermédiaire dune aiguille dinjection. La seringue sans aiguille comprend : un corps de seringue une partie de boîtier destinée à contenir la substance à injecter, avec un élément détanchéité interposé, dans un compartiment de boîtier disposé dans le corps de seringue une partie de compression qui déplace ou rompt lélément détanchéité par compression de la substance à injecter qui est contenue dans la partie de boîtier, la substance à injecter étant éjectée à lextérieur une partie de chemin découlement qui définit un chemin découlement de telle sorte quune ouverture déjection vers l
