A kind of self-action venous detaining needle group,Include a remaining needle fixed cylinder,One be axially displaceably arranged what remaining needle fixed cylinder puncture needle fixed cylinder,The puncture needle of one fixed what puncture needle fixed cylinder,Part is closed in one be arranged what remaining needle fixed cylinder pass with moving radially,And an elastic component between contact what remaining needle fixed cylinder and puncture needle fixed cylinder,It can stop remaining needle fixed cylinder when switch member position one block position of what,Make puncture needle fixed cylinder puncture needle can not be allowed to be maintained at an injection position relative to the movement of remaining needle fixed cylinder,It will not stop remaining needle fixed cylinder when switch member position one releasing position of what,Enable puncture needle fixed cylinder driven by the elastic force of elastic component puncture needle move back avoided in Hou to remaining needle fixed cylinder it is exposed,Can so reach simplified structure,Effect that is easy to assembly and promoting safety in utilization.一種自動式靜脈留置針組，包含有一留置針固定筒、一可軸向移動地套設於留置針固定筒之穿刺針固定筒、一固定於穿刺針固定筒之穿刺針、一徑向移動地套設於留置針固定筒之關關件，以及一頂抵於留置針固定筒與穿刺針固定筒之間之彈性件，當開關件位於一擋止位置時會阻擋留置針固定筒，使穿刺針固定筒無法相對留置針固定筒移動而讓穿刺針保持在一注射位置，當開關件位於一釋放位置時不會阻擋留置針固定筒，使穿刺針固定筒能藉由彈性件之彈力而帶動穿刺針退後至留置針固定筒內避免外露，如此即能達到簡化結構、組裝方便及提升使用安全性的效果。
