To provide a potential detecting driver surely transmitting its notification to a user when being used under noisy environment or in outdoor daylight by improving the conventional potential detecting driver notifying the potential detection by the light and the sound such as a light emitting device and a buzzer.

The potential of a terminal touched by a driver bit 12 in the tip of a grip part 11 starts a vibration motor 15 via a potential detecting substrate 14, the vibration generated thereby is propagated to the user, and the user can confirm the presence of the potential. This constitution provides a sure potential detecting function without affected by environment even in working under the noisy environment and the outdoor daylight.