Niterra Co., Ltd.

Soh Tohara

Yuichi Yamada

Kengo Fujimura

Syoma Tsumagari

A spark plug includes a tubular metallic shell, a tubular insulator held in the metallic shell and having an axial hole, a center electrode held at one end of the axial hole, a metallic terminal member held at the other end of the axial hole, and a resistor element disposed between the center electrode and the metallic terminal member in the axial hole and containing glass and an electrically conductive material. The resistor element has a first resistor layer disposed on the center electrode side and closest to the center electrode and containing titanium oxide, and a second resistor layer disposed on the metallic terminal member side in relation to the first resistor layer and whose titanium oxide content is lower than that of the first resistor layer. The titanium oxide content decreases from the center electrode side toward the metallic terminal member side.

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Nagoya, Japan

Soh Tohara