Ceramic glow plug

A ceramic glow plug comprising:

• a ceramic heater composed of
• a substrate formed of an electrically insulating ceramic and having a columnar shape extending in an axial direction, and
• a resistor having a heat-generating element formed of an electrically conductive ceramic, embedded in a forward end portion of the substrate, and generating heat by resistance heating when energized, lead portions connected to opposite end portions of the heat-generating element and extending rearward in the axial direction, and an electrode taking-out portion extending in a radial direction from at least one of the lead portions and exposed on an outer circumferential surface of the substrate;
• and
• a metallic tubular member in which the ceramic heater is held and which is in contact with an exposed surface of the electrode taking-out portion and electrically conducts with the exposed surface,
• the ceramic glow plug being characterized in that dimensions, in the axial and circumferential directions, of the exposed surface of the electrode taking-out portion both fall within a range of 1.0 mm to 1.8 mm.