| 摘要 |
A protective sleeve for a spark plug includes a center electrode, an insulator, an attachment fitment having an attachment screw section formed on an outer peripheral surface thereof, and a ground electrode. A protective sleeve is disposed in a detachable manner on the outer periphery of the attachment screw section. The attachment fitment includes a flange section that has a diameter larger than that of the attachment screw section on a base end side of the attachment screw section. The protective sleeve includes a main body cylinder section having an inner diameter that is the diameter of the attachment screw section or larger, and smaller than the diameter of the flange section, a large diameter cylinder section having an inner diameter that is the diameter of the flange section or larger, and a step section formed between the large diameter cylinder section and the main body cylinder section. |
