A semiconductor device includes: a chip having a first main surface on one side and a second main surface on the other side; a first region of a first conduction type which is formed on the second main surface side in the chip; a second region of a second conduction type which is formed on the first main surface side of the chip and forms a pn-junction portion with the first region; a device region which is provided on the first main surface; a first groove structure including a first groove, a first insulating film, and a first polysilicon, and partitioning the device region; and a second groove structure including a second groove, a second insulating film, and a second polysilicon, and partitioning the device region on a device region side of the first groove structure.