A semiconductor device has an active region through which current flows and a termination structure region. At a front surface of a semiconductor substrate of a first conductivity type, a first semiconductor layer of the first conductivity type is provided. At a surface of the first semiconductor layer, a lower parallel pn structure is provided. At a surface of the lower parallel pn structure, an upper parallel pn structure is provided in the termination structure region and a first semiconductor region of a second conductivity type is provided in the active region. A width of an upper second column is wider than a width of a lower second column. An interval between the upper second columns is wider than an interval between the lower second columns. A thickness of the upper second column is thicker than a thickness of the first semiconductor region.