The catheter of air (2) and the catheter (2) it is adhered by the basic destal, inside that the catheter (2) inside the channel which is communicated (31) the catheter hub which it possesses (3) and the catheter (2) the needle which the Interpolation passes inside, (4) and the needle (4) it is adhered by the basic destal in order the channel (31) to close the catheter hub (3) end face side and it has the joint possible needle hub (5) the catheter assembly body which in (1), it is laid out, the opening and closing possible opening and closing section (71) the needle which it possesses (7) with, the tube-like object it is not, on the other hand opening (85) the opening and closing section(71) being interposed, in order the catheter hub (3) to communicate with end face side and Tip side, the operating member which is provided (8) with, the needle (7) the communication section which the catheter hub which is provided (3) was provided in the inner circumference section, makes with end face side and Tip side communicate (9) with it possessed, in order the needle (7) with the operating member (8) between, the communication section (9) to close, it was provided, made the vapor pass, the seal component of the tube-like object which at the same time does not make the liquid pass (10) it provided.中空のカテーテル(2)と、カテーテル(2)の基端部に固着され、その内部にカテーテル(2)内と連通する流路(31)を有するカテーテルハブ(3)と、カテーテル(2)内に挿通される針(4)と、針(4)の基端部に固着され、カテーテルハブ(3)の基端側と接続可能な針ハブ(5)とを備えるカテーテル組立体(1)において、流路(31)を塞ぐように配置され、開閉可能な開閉部(71)を有する弁体(7)と、筒状体をなし、その一方の開口部(85)が開閉部(71)に挿入されてカテーテルハブ(3)の基端側と先端側とを連通するように設けられた操作部材(8)と、弁体(7)が設けられたカテーテルハブ(3)の内周部に設けられた、基端側と先端側とを連通させる連通部(9)とを有し、弁体(7)と操作部材(8)の間に、連通部(9)を塞ぐように設けられ、気体は通過させ、且つ液体を通過させない筒状体のシール部材(10)を設けた。
