To reliably prevent generation of a defective generated in the final stage of work by slidably installing a support main body in the shaft direction through an elastic member on an installing member to be installed in a work machine.

A support main body 20 fitted to a front half part of a slide bar 10, can retreat against a spring 24 when shaft directional force acts by the coil spring 24 interposed between a rear end surface 31 of a tool holding body 30 to be installed in a large diameter part 25 on its tip and a tip surface 16 of the slide bar 10. An attachment 50 for a die is fitted from the tip in the tool holding body 30 installed in the support main body 20, and when an installed die 50 is slightly pushed against a work chucked to a main spindle of a lathe, the die 50 familiarly contacts with the work by the coil spring 24. Next, while rotating the work in this condition, required screw cutting work is performed.