A semiconductor device may be provided with a semiconductor substrate, an insulating film disposed on a surface of the semiconductor substrate, at least one electrode disposed on a surface of the insulating film, and a voltage applying circuit configured to apply a first voltage to the at least one electrode. The semiconductor substrate may be provided with a cell region and a non-cell region adjacent to the cell region. The cell region is provided with a semiconductor element, and the non-cell region is provided with a withstand voltage structure. The insulating film may be disposed on a surface of the non-cell region. The at least one electrode may be electrically insulated from the semiconductor substrate. The voltage applying circuit may apply the first voltage to the electrode during at least a part of a first period in which a second voltage is not applied to the semiconductor element.