Safety indwelling needle

A safety indwelling needle comprising:

• an inner needle unit which includes an inner needle, an inner needle hub provided on a proximal end of the inner needle, a needlepoint provided at a distal end of the inner needle and a needle protecting member disposed at a distal side of the inner needle hub;
• and
• an outer needle unit which includes an outer needle having a lumen and an outer needle hub provided on a proximal end of the outer needle,
• said safety indwelling needle being characterized in that the needle protecting member includes an extendable housing unit disposed between a distal end of the inner needle hub and a proximal end of the outer needle unit and being detachably connected to said outer needle unit, said inner needle extending through a distal end of said housing unit and through the lumen of the outer needle in a state in which the housing unit is not extended, the needlepoint of the inner needle being stored in the needle protecting member in a state in which the inner needle is withdrawn from the lumen of the outer needle and the housing unit is extended, and said inner needle being formed with an irregular portion on a surface thereof, which irregular portion engages a proximal end of the housing unit and causes said housing unit to extend as said inner needle is withdrawn from the lumen of the outer needle and the needlepoint of the inner needle to be stored in the housing unit in the state in which the housing unit is extended,
• wherein the housing unit is provided with a hooking member on the proximal end which can be engaged with said irregular portion on the surface of the inner needle so as not to be relatively moved with respect to the housing unit but to extend the extendable housing unit.