Patent ID: 7798387

Claim:
A friction stir welding apparatus configured to mount a machine tool to a friction stir welding apparatus body, comprising: a retaining means which is mounted at one end portion thereof to the friction stir welding apparatus body and is provided with a plurality of mounting passages on a peripheral surface of the other end portion thereof, the mounting passages being arranged to be spaced apart from each other in a circumferential direction and having opening ends which open on an opposite side of the one end portion; a mounting means having a plurality of mounting members which are respectively inserted through the opening ends of the plurality of mounting passages and are respectively fitted to tip end portions of the plurality of mounting passages; a machine tool provided on the mounting means, the machine tool being fitted at one end portion thereof to the other end portion of the retaining means and having a friction stir welding portion at the other end portion thereof, wherein the mounting means is provided with a biasing means configured to exert a force on the machine tool toward the retaining means.