An electronic drum system includes an electronic drum having a shell, a drum head stretched across an opening of the shell, a vibration sensor converting vibrations of the drum head to an electric signal and a damper held in contact with the reverse surface of the drum head; when a drummer strikes the drum head with a stick, the drum head is shaken, and vibrations follow; the damper is held in contact with a certain area on the reverse surface, and the shake and vibrations are propagated from another area free from the damper to the vibration sensor; the shake is surely propagated to the vibration sensor, and the vibrations are rapidly decayed; for this reason, the vibration sensor exactly discriminates the shake from the peaks of the vibrations, thereby preventing an electronic sound generator from unintentionally repeated electronic beats.