A head protection air bag apparatus comprises an air bag, an air bag cover for covering the air bag, an inflator for supplying the air bag with a gas for inflation, and an assist grip. In the burring method, a width of a clearance formed between the burring hole and the burring punch is in a range not less than 60% and not more than 115%, preferably not less than 65% and not more than 100%, and more preferably, not less than 75% and not more than 95%, of a thickness of the metal sheet, before the metal sheet goes through a burring process. The garment may include a pocket generally corresponding in shape to desired shape of the neck pillow. Additional control logic is configured to determine whether a clock signal is enabled in output control logic circuitry according to the multiple-cycle command and logic level generated in the output logic circuitry.