To receive a predetermined traction load and to prevent a shock absorbing function proper to a bumper reinforcement like being crashed in collision from being damaged, with regard to the detachable towing hook installation structure of the bumper reinforcement.

The screw part 18A of a towing hook 18 is screwed into the screw hole 20A of a towing hook fitting member 14 fixed to the bumper reinforcement 14 to fix the towing hook 18 to the bumper reinforcement 14. A plate-like base 20-1 extending in the longitudinal direction of the bumper reinforcement 14 is fixed to the front wall of the bumper reinforcement 14 by welding. The towing hook fitting member 14 is fixed only at the front wall 14A of the bumper reinforcement 14.