An outer needle for an epidural anesthesimeter having an opened edge face (3) thereof formed by partially bending a stainless steel hollow tube to form a tip end portion (2) and cutting the tip end portion (2), wherein the tip end portion (2) is bent gently so that the tip end of the anesthesimeter inserted into the outer needle (1) can slip and easily protrude from the opened edge face (3) even when it contacts the inner surface of the tip end portion, the opened edge face (3) is formed, at the side view, into a wave form in which the front half thereof is convex (4) and the rear half is concave (5), and, at the top view, into an oval shape or a corner-rounded rectangular shape with longer sides outwardly curved, cutting edge angles at the outer and inner front ends (6, 7) of the opened edge face (3) have not smaller than double the angle at the conventional opened edge face, and the outer needle satisfies the following conditions: 1. Ease with which an inserted anesthesimeter can protrude. 2. No possibility of the outer front end of the opened edge face damaging the dura mater when pierced into the epidural portions. 3. No possibility of a catheter being caught by or damaging the opened edge face when the catheter that has been inserted is pulled off. |