PURPOSE: To locate and guide plural tools mounted on a multi-spindle head and a work to be machined which are attached to a mounting jig with high accuracy, and hold the multi-spindle head and the mounting jig firmly each other.

CONSTITUTION: This guide device is provided with a guide bar 90 which is disposed so that it may advance and retreat from/into a multi-spindle head 16, a linear bush 98 which is mounted on the multi-spindle head 16 and guides the guide bar 90 so that it may advance and retreat with the outer periphery surface of the guide bar 90 pressed, and a tightening means 112 which is mounted on a rotary jig 24, and is shrunk by fluid pressure to clamp and fix the outer periphery surface of the guide bar 90 and integrate the guide bar 90 and a rotary jig 24.