A computer calculates bit patterns of syndromes for all candidate bit patterns of reception words that are input in ECC-EOR circuits of a logic circuit. A headrest body is provided to protect the passenger at the vehicle rear crash. This entire central zone is a residual surface compressive stress zone having a residual surface compressive stress value ranging from 10 MPa to 30 MPa. The script is repaired based on the change type. Each guide tube is affixed to a mounting bracket that is detachably connected to the C-channel to support the guide tube within the tailgate.