SPARK PLUG AND INTERNAL-COMBUSTION ENGINE

Provided is an ignition plug (15) that has an antenna (54) for emitting high-frequency EM waves to combustion chamber (20) of an internal combustion engine (10), wherein the propagation velocity of the flame is augmented using the high-frequency EM waves emitted from the antenna (54). The ignition plug (15) has an ignition plug body (30) and an antenna (54). The antenna (54) is located on the front-tip side surface of the cylindrical second conductive member (33) within the ignition plug body (30), which accommodates a rod-shaped first conductive member (31) and cylindrical insulation (32) surrounding the first conductive member (31).