To assure the prevention of a circuit element from being broken when there is wrong reverse connection by significantly improving the driving performance of a driver, and attain miniaturization and cost reduction.

This preventing device comprises a detection function of reverse connection; a function of disconnecting the state of the reverse connection if the reverse connection is detected; and a function of setting an on-resistance value and a voltage drop below prescribed values at the time of energization so that the driving performance of a driving element is derived to higher than the prescribed value.