Indwelling needle assembly

An indwelling needle assembly for introducing a catheter into a vascular system, the indwelling needle assembly comprising:

• a needle capable of being slidably fitted in the catheter and insertable into the vascular system;
• a base body fixed to a proximal end of the needle;
• a first sleeve slidably fitted around the base body, the first sleeve being movable between a first position to expose a distal end of the needle and a second position to conceal the distal end of the needle;
• an elastic body intervening between the base body and the first sleeve so as to urge the first sleeve toward the second position;
• a second sleeve telescopically fitted to the first sleeve, the second sleeve including a latching device configured to hold the first sleeve at the second position;
• a cover fixed to the base body, the cover being so dimensioned as to house the first sleeve and the second sleeve when the first sleeve is at the first position;
• and
• a lock configured to releasably hold the first sleeve at the first position;
• wherein the second sleeve is provided to intervene between the first sleeve and the cover, the second sleeve is integrally movable with the first sleeve so that the first sleeve and the second sleeve are slidably movable with respect to the needle, the base body and the cover.