PURPOSE: To make a magazine for storage of tool in a small size by incorporating a tool replacement arm which provides possibility of taking out onle a desired tool while the tool holder is left mounted on the spindle.

CONSTITUTION: Shaft 5 of a tool holder TH is fixed in a spindle 12. Straight collet installed in the holder is expanded and contracted by turning a fastening nut 20. When this nut is released by a tool fastening/loosening member 30, the collet is expanded to release the shank part of drill. Arm 15 inserts and draws out the tool T1 and sets the shank part 5 of a new tool T2 into the collet. Then the nut 20 is rotated reversely for fastening. The tool magazine M0 is mounted on a bracket 14 behind the column 10, and an index motor M2 locates the intended tool holding cylinder 40 in the tool replacement position ii mating with the tool holder TH of the spindle 12.