A glow plug includes: a tubular body (2) having at one of its ends a plug head as well as a fixing zone including elements (12, 13) for being fixed in a bore, an arm (4) mounted on the body (2) of the plug at the end opposite to the plug head, and a pressure sensor (8) sealingly insulated from the corresponding cylinder. The arm (4) is fixed to an elastically deformable tubular zone (17) designed to project inside the cylinder. The pressure sensor (8) is mounted between the arm (4) and a support component (18) fixed inside the tubular body (2).