To enable shafts of hook members to be inserted in insertion holes and properly screwed on nut members even when enabling deformation of hook members to be properly suppressed by making the insertion holes provided in a bumper reinforcement smaller.

The nut members 16, attachment plates 20, brackets 22, the bumper reinforcement 24, and crash boxes 26 are integrally welded beforehand to constitute the hook mounting module 12, which is attached in that state to side members 14 by bolts 32 via an attachment plates 20, so that mutual alignment precision can easily be secured at the stage of welding them integrally. Thereby, misalignment is suppressed between the nut members 16 provided on the attachment plates 20 and reinforcement washers 74 provided on the bumper reinforcement 24. By making small through-holes 72 (insertion holes) of the reinforcement washers 74, deformation of the shafts 54 can be suppressed more properly.