A device includes: a cylindrical body formed of an elastic material and a slit formed along a longitudinal direction of the cylindrical body from one end to an opposite end of the cylindrical body, a distal end of a nail being inserted to be held in the slit. The cylindrical body includes: plural pairs of holding teeth plurally divided in the longitudinal direction of the cylindrical body by dividing grooves formed from the slit along a circumferential direction of the cylindrical body such that the holding teeth of each pair are opposed to each other across the slit to hold the distal end of the nail and coupling pieces configured to couple adjacent ones of the holding teeth on an opposite side of the slit.
