Patent ID: 8372105

Claim:
A puncture instrument comprising: a case; a needle assembly movably disposed in the case and including a needle and a hub holding the needle; a hub passage for axially guiding the hub, the hub passage being disposed in the case; a needle passage disposed in the case and communicating with the hub passage, the needle passage having a distal end opening for allowing a tip end of the needle to project therethrough; at least one arm having a first junction on an end thereof connected to the hub and a second junction on another end thereof, the arm being inclined from the first junction toward a proximal end of the case in an initial state; a push rod joined to the second junction and extending toward the proximal end; a pusher for pushing the push rod toward a distal end of the case; and a fulcrum member separate from the arm in the initial state and abutting against a portion of the arm when the arm moves; wherein when the push rod is pushed toward the distal end by the pusher, the arm pushes the needle assembly toward the distal end, brings the portion thereof into abutment with the fulcrum member, and turns about the fulcrum member, so that the arm is inclined from the first junction toward the distal end thereby to pull back the needle assembly toward the proximal end.