When the detonation caused by pre-ignition and post-ignition, it is generally known that strong vibrations from the combustion chamber develop from impact of that combustion pressure. This will affect the engine. Methods to accurately measure the strength of this detonation and its usage are being considered and used from various viewpoints. We measure this detonation quantitatively by the detonation counter. This is done in order to bring out optimum performance of the engine, specifically the spots, carburetor settings, and ignition timing. Where adjustments must be made and it is useful as a tool for judging, conducting, and setting adjustment directions and volume quickly and accurately. Furthermore, simplification of this system has the enable it to be sold on the market. As a result of this, it now has spread to and is being used for racing base.