To provide a tool device for a rotary machine tool, capable of performing quick, flexible, and comfortable tool replacement while achieving the stable and firm tool device.

A tool device for a rotary machine tool includes a spindle 16 rotatably housed in a housing 12 via bearing sets 28 and 28', and tool holders 14, 24, and 26 including a tool mandrel 14 are clamped in the spindle to fix a tool 20. The tool holders 14, 24, and 26 to which the tool 20 is fixed are clamped in the spindle 16 so that the bearing of the front side of at least one of the bearing sets 28 and 28' and the set center 30 of the bearing set can be surrounded with at least one of the tool mandrel 14 and the tool 20.