stable and quickly with a simple structure and blocking communication of the chemical liquid flow path The thing to switch, both the prevention of backflow of administration and the blood like a stable chemical liquid such as can be effectively realized, and to provide a needleless connector of the new structure. With the hollow elastic body 16 bottomed tubular which is open toward the outlet side of the liquid medicine flow channel 80 with respect to housing portion 20 formed in the housing 12 is accommodated arranged, the bottom wall 70 of the hollow elastic body 16 The center projection 66 which protrudes toward the central portion on the inlet side of the liquid medicine flow channel 80 is provided, by the insertion of the male luer 86 is pressed the tip end of the center projection 66 of the hollow elastic body 16 bottom wall 70 a peripheral wall 68 is elastically deformed so as to enter the inside, with the volume of the liquid medicine flow channel 80 formed between the inner surface of the outer surface and the housing portion 20 of the hollow elastic body 16 is expanded, the male luer 86 is withdrawn is hollow elastic The volume of liquid medicine flow channel 80 is to be reduced by the elastic deformation of the body 16 is released.薬液流路の連通と遮断を簡単な構造で安定して且つ速やかに切り替えることで、薬液等の安定した投与と血液等の逆流の防止を何れも有効に実現することができる、新規な構造のニードルレスコネクターを提供する。 ハウジング12に形成された収容部20に対して薬液流路80の出口側に向かって開口する有底筒状の中空弾性体16が収容配置されていると共に、中空弾性体16の底壁70の中央部分から薬液流路80の入口側に向かって突出する中央突部66を設けて、雄ルアー86の挿入により中央突部66の先端が押されて中空弾性体16の底壁70が周壁68内に入り込むように弾性変形されて、中空弾性体16の外面と収容部20の内面との間に形成された薬液流路80の容積が拡大されると共に、雄ルアー86が抜き取られて中空弾性体16の弾性変形が解除されることにより薬液流路80の容積が縮小されるようにした。
