To provide a reamer suitable for machining a large hole used for a valve body or an oil pump at high speed rotation, at high feed and with high accuracy.

This tip holder exchange type drilling tool is a tip holder exchange type reamer including: a shaft-like tool body 1 having a taper part which becomes gradually smaller in as it goes toward one end; a tip holder 2 having a taper hole 21 fitted to the taper part 12; a holder pusher 3 moved toward the tip of the tool body 1 to loosen engagement of the tip holder 2 and the tool body 1; and a tip 7 fixed to the tip holder 2. The holder pusher 3 is rotated in relative to the tool body 1 to move in the direction of shaft center, thereby pushing out the chip holder 2.