To provide a puncture adapter for an ultrasonographic apparatus which enables the use of a puncture needle with any diameter and prevents the center of fixation from being shifted by the influence of the needle diameter, or the like.

This puncture adapter 30 includes a puncture needle holding mechanism in which the inside diameter of a cylindrical body for passing and holding the puncture needle 2 is varied correspondingly to the outside diameter of the puncture needle 2 in a guide part 31. The puncture needle holding mechanism has a tapered outer cylinder 32, the inner surface of which is gradually reduced in the inside diameter from the substantially central part in the axial direction toward the tip, the above cylindrical body is an inner cylinder 33 inserted and disposed so that the outer peripheral surface is opposite to the inner surface of the outer cylinder 32, and provided with a claw-like piece 33c at the tip. The inner cylinder 33 is advanced to the outer cylinder 32 by screw-fitting operation of a male screw part 33a and a female screw part 32a formed on the respective rear end parts thereof, and an opening surface N of the claw-like piece is narrowed by the advance to fix the puncture needle 2.