Abstract: A fine adjusting method of the feed amount of a boring cutter includes the following steps: a shank body rotates around its axes as the center of a circle to make the cutter tip rotate around its axes as the center of a circle which is apart away from the axes with an offset distance e therebetween so as to change the feed amount. An adjusting device which can achieve the fine adjusting method of the feed amount of the boring cutter includes: a shank body which has a tapered bore, and the axes of the tapered bore is apart away from the axes of the shank body; a rotating cone body which cooperates with the tapered hole; and the rotating cone body is provided with another tapered hole; a changeable cutter holder which is installed in the tapered hole of the rotating cone body; and a drive mechanism which mounts on the shank body and drives the rotating cone body to rotate, therefore makes the changeable cutter holder rotate so as to achieve the micro-feed of the cutter tip.