PROBLEM TO BE SOLVED: To provide a needleless injection device that forms an appropriate state of contact between an injection port from which a substance to be injected is injected and an injection object.SOLUTION: A needleless injection device includes an inflatable bag body arranged so as to surround an outer peripheral surface of an injection object, a needleless syringe without an injection needle, and a gas supply device for supplying inflation gas to the bag body. The needleless syringe includes a nozzle part for injecting a substance to be injected toward the injection object surrounded by the bag body, whose injection port is in a state of facing the injection object. The bag body includes a first bag part which is any region other than a region where the needleless syringe is disposed, and is arranged so as to pressurize the injection object by inflation, and a second bag part arranged in a region to sandwich the nozzle part between the injection object and itself so as to press the injection port to the injection object side by inflation.SELECTED DRAWING: Figure 1【課題】注射目的物質が射出される射出口と注射対象物との適切な接触状態を形成する無針注射装置を提供する。【解決手段】注射対象物の外周面を取り囲むように配置される膨張可能な袋体と、注射針を有しない無針注射器と、袋体に膨張用気体の供給を行う気体供給装置と、を備える、無針注射装置である。なお、無針注射器は、袋体が取り囲む注射対象物に向かって注射目的物質を射出するノズル部を有し、その射出口は注射対象物に対向した状態となる。そして、袋体は、無針注射器の配置部位を除く部位の何れかであって、膨張により注射対象物を加圧するように配置される第１袋部分と、膨張により射出口を注射対象物側に押し付けるように、該注射対象物との間にノズル部を挟む部位に配置される第２袋部分と、を有する。【選択図】図１
