| 摘要 |
[Objective] To more reliably prevent a deterioration of a seal member due to heat. [Means for Solution] A glow plug 1 includes a cylindrical housing 2, having an axial hole 7 extending in a direction of an axis CL1, which includes an external thread portion 8 for coming into threaded engagement with an internal thread portion FS provided on a mounting hole HO of an internal combustion engine EN; a ceramic heater 4 inserted in the axial hole 7 in a condition in which at least a leading end portion of the ceramic heater 4 protrudes from the leading end of the housing 2; and a center pole 3, having a bar shape extending in the direction of the axis CL1 and inserted into the axial hole 7, which forms an energizing path to the ceramic heater 4. An annular seal member 31 formed from an insulating material is disposed between the inner periphery of the housing 2 and the outer periphery of the center pole 3 within a range of formation of the external thread portion 8 along the axis CL1. |
