In order to provide a connection device whereby an operation for connecting and locking a device connector to a container connector and an operation for unlocking and disconnecting the same can easily be performed, a connection device 10 is provided with a syringe connector 100, a container connector 20, a second arm part 232, and a locking recess 67. The syringe connector 100 is provided with a head sleeve 180, a needle 170, a needle seal 200, and an outer body main body 11 for forming a liquid flow path communicated with the inside of a syringe 6. The container connector 20 is provided with a needle part 50, a liquid flow path formation part L3, and a container seal 70. The second arm part 232 and the locking recess 67 are engaged in a state in which the needle 170 penetrates through the needle seal 200 and the container seal 70 and is communicated with the liquid flow path formation part L3.提供一種能夠使將器具連接具與容器連接具作連接並作鎖死之操作和將鎖死以及連接作解除之操作變得簡單之連接器具。 連接器具(10)，係具備有注射器連接具(100)、和容器連接具(20)、和第2腕部(232)、以及鎖死用凹部(67)。注射器連接具(100)，係具備有形成與注射器(6)內相通連的液體流路之外輪廓體本體(11)、和頭套筒(180)、和針(170)、以及針密封構件(200)。容器連接具(20)，係具備有針部(50)、和液體流路形成部(L3)、以及容器密封構件(70)。第2腕部(232)和鎖死用凹部(67)，係在使針(170)貫通針密封構件(200)和容器密封構件(70)並與液體流路形成部(L3)作了通連的狀態下，而相互卡合。
