To provide a reamer or file supporting method and a supporting jig which can orderly array a reamer or file used for dental treatment and makes it possible to carry out dental work while supporting at the hand of an operator at the same time.

A supporting member 2 is housed in a housing case 3 and the necessary reamer or file is positioned at recess parts 9 and 10 for positioning the side edge boards 7 and 8 of the left/right case bodies 4 and 5 of the case 3 and array-supported while being stung. After then, both left/right bodies 4 and 5 are opened through a hinge 6 to take out the member 2 and this is held by inserting/holding between the fingers of the operator's hand grasping the treating jig.