For the purpose of realizing of a method of minimally-invasive therapy for spinal canal stenosis, it is intended to provide a therapeutic device capable of stationing an interspinous process spacer without the need of large skin incision or ligamentous tissue incision and also without the need of detaching of the paraspinal muscle from the spine. There is provided an interspinous process spacer comprising conoid screw region (2) to be screwed into a processus spinosus interspace spacer region (3) disposed in the longitudinal direction of the screw region (2) head region (4) capable of free interlocking with a tool arbitrarily and through-hole (5) passing through the axial centers of screw region (2), spacer region (3) and head region (4). The processus spinosus interspace can be smoothly enlarged by screwing of the screw region (2) into the processus spinosus interspace. The spacer region (3) is pinched upon passing of the screw region (2) through the processus spinosus interspace to thereby attain enlarging and fixing of adjacent processus spinosus interspaces. The interspinous process spacer can be guided to an interspinous position by inserting a guide member in the through-hole (5) provided along the axial centers of screw region (2) and spacer region (3) and carrying out penetration into the body along the guide member.
