| 摘要 |
A spark plug (100) includes a center electrode (20) extending in the direction of an axis (CL), an insulator (10) having an axial hole (12) which extends in the direction of the axis (CL) and in which the center electrode (20) is disposed, a metallic shell (50) disposed around the insulator (10), a first ground electrode (30A) having a first surface (39A) facing a side surface of the center electrode (20) in a radial direction so as to form a first gap (GA), and a second ground electrode (30B) having a second surface (39B) facing the side surface of the center electrode (20) in the radial direction so as to form a second gap (GB). A relation 60° ‰¤ ¸ ‰¤ 150° is satisfied, where ¸ is a smaller one of angles formed between a first line connecting the axial line and the center of the first surface (39A) and a second line connecting the axis and a center of the second surface (39B) when viewed from a forward end side toward a rear end side in the direction of the axis. The metallic shell (50) has a specific plane (VL) which bisects the metallic shell (50) such that all the ground electrodes (30A, 30B) are located on one side of the plane (VL). |
