Disclosed is a trocar, comprising a trocar sleeve, a sealing structure and obturator, wherein the trocar sleeve comprises a bowl-shaped proximal end housing part, a distal end portion and a sheath portion between the two the sealing structure comprises a top shell and a bottom shell integrated with each other and the obturator comprises a central shaft and a proximal end portion which is located at the proximal end of the obturator designed to be held by a surgeon the axial direction of the trocar is defined by the extension direction of the central shaft which also has an obturator tip at the distal end to perform puncturing the central shaft runs through the sheath portion of the trocar sleeve and the sealing structure in a sealed manner and the obturator tip of the central shaft extends out of the distal end portion of the trocar sleeve when the trocar is assembled. The trocar disclosed by the present invention is characterized in that: the axial dimensions of the proximal end housing portion of the trocar sleeve, the top shell of the sealing structure and the proximal end portion of the obturator in the axial direction of the trocar respectively are d1, d2 and d3, and d3 is equal to or greater than 1/2 of the sum of d1, d2 and d3. The trocar disclosed by the present invention is advantageous in that when the trocar is in use, the trocar sleeve housing and the sealing structure are unlikely to be separated from each other due to the torque exerted by the surgeon to the joined portion between the trocar sleeve and the sealing structure.本發明公開了一種穿刺器,包括:套管,其包括大致呈碗型的近端容納部分、遠端部分以及位於兩者之間的筒體部分;密封艙,其包括一體連接的上殼和下殼;穿刺杆,其包括芯杆和位於芯杆的近端處供外科醫生握持用的近端部分,所述芯杆的延伸方向限定了穿刺器的軸向,芯杆在其遠端具有用於實現穿刺功能的穿刺頭端,並且芯杆在穿刺器的裝配狀態下密封性地貫穿套管的筒體部分和密封艙、同時芯杆的穿刺頭端突伸出套管的遠端部分;其特徵在於:穿刺套管的近端容納部分、密封艙的上殼、穿刺杆的近端部分在穿刺器的軸向方向上的軸向尺寸分別為d1、d2、d3,並且d3被設定為等於或大於d1、d2、d3之和的1/2。在使用根據本發明的穿刺器時,能夠防止穿刺器的套管和密封艙例如由於外科醫生施加在穿刺器的套管和密封艙之間的聯結部分上的轉矩而分離開。1a‧‧‧頭部120‧‧‧近端部分210‧‧‧上殼310‧‧‧近端容納部分d‧‧‧軸向尺寸d1‧‧‧軸向尺寸d2‧‧‧軸向尺寸d3‧‧‧軸向尺寸
