Disclosed is a needleless access device which includes a housing member and an elastic component. A needleless injection end and an output connector end are respectively formed at the two end of the housing member and the elastic component in the housing member includes a compression portion, a compression body and a compression seat which are connected together in sequence. The top surface of the compression portion is recessed to form a concave portion and the compression body is formed as a hollow hemisphere structure. When a needleless injector is inserted into the needleless injection end to apply pressure to the compression portion, the compression seat is recessed, and the fluid from the needleless injector flows from the concave portion of the compression portion through a gap to the output connector； when the needleless injector stops applying pressure to the compression portion, the concave portion of the compression seat ejects so that the compression seat reverts back to its original state.一種免針式接頭裝置，包含一殼體以及一彈性構件，殼體的二側分別形成為無針注射端及輸出連接端，而彈性構件位於殼體中，並具有依序相接的一受壓部、一受壓本體及一受壓座，受壓部之頂面向內凹陷形成有一凹部，以及受壓座形成為一中空半球結構，當無針注射器自無針注射端插入而對受壓部施壓時，受壓座向內凹入，且自無針注射器流出之液體流經受壓部之凹部並通過空隙往輸出連接端流動，當無針注射器停止對受壓部施壓時，受壓座向外彈出而恢復原狀。
