Provided is a fitting tool which can reduce the discomfort associated with the wear of a breathing mask. The fitting tool is intended for a breathing mask which covers the nares of a user and provides a pressurized gas to the nares thereof. The fitting tool has a slender shape, and is equipped with both a pair of connecting members, first ends of which are to be connected to the breathing mask, and a pair of fixing members which are to be connected to second ends of the connecting members and which are to be inserted into the concavities present on the insides of the tragi of the user. Thus, the fitting tool can protect the user from the discomfort associated with the restraints around the head.
