Patent ID: 7402941

Claim:
A spark plug comprising: a cylindrical insulator having an axial hole extending in an axial direction; a center electrode held in said axial hole on a leading end side; a connecting terminal held in said axial hole on a trailing end side; and a sealing layer provided in said axial hole and comprising a glass sealing material containing a glass component and a metallic component, said sealing layer including a first sealing layer containing a first glass sealing material and a second sealing layer containing a second glass sealing material laminated in an axial direction of said axial hole, said first sealing layer contacting said center electrode, and said second sealing layer contacting said connecting terminal, wherein said second glass sealing material has higher fluidity than that of said first glass sealing material at a temperature higher than a softening point of a glass component contained in said sealing layer, and wherein a content of the metallic component in said first sealing layer is larger than a content of the metallic component in said second sealing layer.