A covering processing tool performs a covering process of a cable connection portion and is provided with a first tubular unit extending in an axial direction, a second tubular unit disposed so as to surround the first tubular unit on an outer peripheral side, and a third tubular unit disposed so as to surround the first tubular unit on the outer peripheral side. The second tubular unit is installed on the first tubular unit so when extracting a first diameter expansion holding member of the first tubular unit, by supporting the second tubular unit from an outer peripheral side, relative movement in an axial direction and a circumferential direction of the first tubular unit relative to the second tubular unit is suppressed.