PURPOSE: To enable fast response ignition, by mixing a common matrix with a low-cost sample base ceramics and a base ceramics with the conventional metal powder to build an conducting element of it plug.

CONSTITUTION: A conducting element 1 is built up of a thermet material that makes a ceramic base matrix of the conducting element 1 equal in nature to the ceramics of an insulator element 2. A conducting phase uniformly and homogeneously dispersed in the matrix is a particulate metal phase and a thermal expansion factor of the particulate metal phase differs by four times or less from the thermal expansion factor of the ceramic base matrix. The particulate metal phase is dispersed in the ceramic base matrix and the particles of the particulate metal phase are small in the size thereof enough to keep the internal stress caused by a thermal change received by a glow plug during the use below a limit at which the ceramic phase may crack. This can guarantee electric conductivity for a thermet in a range sufficient to produce a quick response glow plug heating element.