To provide a fireproof attachment mounting tool that can easily spread a plate spring to a pipe diameter, mount a fireproof attachment directly to a resin pipe from the tip side of the plate spring of the fireproof attachment and mount the fireproof attachment on the resin pipe, hardly sliding the fireproof attachment.

The fireproof attachment mounting tool comprises an outer cylinder part 10 having almost the same inner diameter to be fitted to the outer diameter of the resin pipe, and an inner cylinder part 20 formed longer than the outer cylinder part to extend from the outer cylinder part at one end of the outer cylinder part 10. The inner cylinder part 20 has a cylinder part arranged inside the outer cylinder part 10 at least and having an outer diameter almost the same as the inner diameter of the resin pipe.