An spark ignition type internal combustion engine allows the spark discharge by the ignition plug to react with the electric field created in the combustion chamber and generates the plasma, thereby igniting the fuel air mixture to reduce the emission of the unburned fuel and to improve fuel efficiency of the internal combustion engine in a spark ignition type internal combustion engine that allows an electric field created in a combustion chamber to react with a spark discharge by an ignition plug and generates plasma, thereby igniting fuel air mixture. The engine includes an electromagnetic wave emission device that emits an electromagnetic wave in the combustion chamber when the fuel air mixture is combusted, and a protruding member protruding from a partitioning surface that partitions the combustion chamber. At least a part of the protruding member is made of a conductor.