Glow plug with ceramic heating element having electrode attached thereto

A ceramic heater comprising a metallic shell with a tip end, wherein said metallic shell has at its tip end a seat surface that abuts a structural body when said ceramic heater is attached to the structural body, said ceramic heater further comprising a ceramic heating member disposed within said metallic shell such that a tip end portion is projected from said metallic shell, said ceramic heating member comprising:

• a ceramic body;
• a conductive ceramic element embedded in a portion of said ceramic body corresponding to the end portion of said ceramic heating member and including a direction-changing portion extending from one base end thereof and changing directions to extend to the other base end thereof and two straight portions extending in the same direction from the corresponding base ends of the direction-changing portion, said conductive ceramic element being disposed such that the direction-changing portion corresponds to the end portion of said ceramic heating member;
• and
• two electrodes connected to said conductive ceramic element such that one end of one electrode is embedded in one end of said conductive ceramic element, and one end of the other electrode is embedded in the other end of said conductive ceramic element, such that upon application of electricity to said conductive ceramic element through said electrodes, said conductive ceramic element generates heat through electrical resistance, wherein said electrodes are disposed such that a distance L between the ends of the electrodes embedded in said conductive ceramic element and the end of the seat surface of said metallic shell is set so as to satisfy an expression L≦1 mm, where the distance L is considered negative when the ends of the electrodes are located within said metallic shell.