The present invention provides a needleless dispenser equipped with an infusion device that does not generate positive and negative pressures and can prevent problems of blood and drug backflow and residuals in a patient. A cover body 1 having a medication port, a connector 2 having a storage chamber, and a positive / negative pressure-free infusion device 3 provided in the cover body and the connector storage chamber are included. The infusion device includes a first fitting component 31, a second fitting component 32, and an infusion component 33 inserted between them, and the first fitting component and the second fitting component are connected to the medication port 10. By being compressed and deformed by the injection head of the syringe, the infusion part is repeatedly connected or closed, thereby achieving a drug flow that does not generate positive and negative pressure. A good closed condition is achieved during normal times, making it difficult for outside contamination to enter and reducing the chances of patient infection. [Selection] Figure 2【課題】患者の血液、薬剤の逆流及び残留の問題を防止できる正負圧力無発生輸液装置を具えた無針式投薬器を提供する。【解決手段】投薬口を具えたカバー体１と、収容チャンバを具えたコネクタ２と、カバー体とコネクタ収容チャンバ内に設けられた正負圧力無発生輸液装置３を包含する。輸液装置は第１嵌合部品３１と第２嵌合部品３２及び両者の間に挿入される輸液部品３３を包含し、第１嵌合部品と第２嵌合部品が投薬口１０に接続された注射器の注射ヘッドにより圧迫されて変形することで、輸液部品に反復して接続或いは閉じた状態を構成させ、これにより、正負圧力を発生しない薬剤の流れを達成する。平時には良好な閉じた状態を達成して、外界の汚染を侵入させにくくし、患者が感染する機会を減らす。【選択図】図２
