Patent ID: 8519306

Claim:
A glow plug comprising a pressure sensor and a heater, the glow plug further comprising: a position-defining member which defines a positional relationship between the pressure sensor and the heater, and which has a coefficient of thermal expansion greater than that of the heater, wherein the pressure sensor is fixed at a predetermined sensor reference position relative to the position-defining member; the heater is held by a heater-holding member in such manner that an attachment position of the heater-holding member to the heater is displaceable, with a change in external pressure, relative to a heater reference position defined by the position-defining member; and a displacement transmission member whose coefficient of thermal expansion is greater than that of the position-defining member is arranged between the heater and the pressure sensor so as to transmit displacement of the heater to the pressure sensor, wherein the heater-holding member is fixed to the housing, holds the heater, and deforms so as to permit displacement of the attachment position relative to the heater reference position along a direction of an axis connecting first and second ends of the housing.