Sonic-type level detector is widely used in the worksite of all industries. Single-bar vibrated level detector is one of the sonic-type level detectors. It is hanging and impact proof and it is very sensible. Its single-bar structure help it can be used widely. Similarly as the sonic-type level detector, it adopts resonance principle that the vibration produced under electrical parts driving. Only the detect bar is covered with material, the vibration will reduce.