A spark plug for combustion chamber of a gas turbine engine including: an external body forming ground electrode, intended to be received mainly in a bypass of the combustion chamber; an internal central electrode; and an interposed insulator with clearance between the external body and the internal electrode, is provided. The spark plug terminates in a nose forming portion to be received in the flame tube of the chamber of the combustion chamber, and a semi-conductor element being interposed between the central electrode and the ground electrode at the level of said nose forming portion. The external body includes at least one cooling air inlet which communicates inside the spark plug with at least one outlet arranged at the level of the nose forming portion.