A semiconductor device comprising: a semiconductor layer having a first plane and a second plane, the first plane and the second plane corresponding respectively to the upper surface and the lower surface of the semiconductor layer; a first electrode in contact with the first plane; a second electrode in contact with the second plane; a first semiconductor region of a first conductivity type provided in the semiconductor layer; a second semiconductor region of a second conductivity type provided between the first semiconductor region and the first plane, the second semiconductor region being in contact with the first plane, the second semiconductor region being electrically connected to the first electrode; and a third semiconductor region of the second conductivity type surrounding the second semiconductor region, the third semiconductor region provided between the first semiconductor region and the first plane, the third semiconductor region being in contact with the first plane, the third semiconductor region including a first region, a second region, and a third region, the second region being further away from the second semiconductor region than the first region, the third region being further away from the second semiconductor region than the second region; wherein, the second semiconductor region and the third semiconductor region are disposed in a termination region surrounding an active region of the semiconductor device, the third semiconductor region adjoins the second semiconductor region, the second region adjoins the first region, the third region adjoins the second region, an amount of second-conductivity-type impurities at an arbitrary position in the first region, the second region, and the third region is less than an amount of second-conductivity-type impurities at an arbitrary position in the second semiconductor region, an amount of second-conductivity-type impurities in at least a portion of the first region is less than an amount of second-conductivity-type impurities in at least a portion of the second region, an amount of second-conductivity-type impurities in at least a portion of the third region is less than an amount of second-conductivity-type impurities in at least a portion of the second region, and the amount of second-conductivity-type impurities means an integrated value of the amount of second-conductivity-type impurities in a depth direction at a specific position; the device being characterised in that it comprises a fourth semiconductor region of the first conductivity type provided between the first region and the first semiconductor region, the fourth semiconductor region having a higher first-conductivity-type impurity concentration than the first semiconductor region. a semiconductor layer having a first plane and a second plane, the first plane and the second plane corresponding respectively to the upper surface and the lower surface of the semiconductor layer; a first electrode in contact with the first plane; a second electrode in contact with the second plane; a first semiconductor region of a first conductivity type provided in the semiconductor layer; a second semiconductor region of a second conductivity type provided between the first semiconductor region and the first plane, the second semiconductor region being in contact with the first plane, the second semiconductor region being electrically connected to the first electrode; and a third semiconductor region of the second conductivity type surrounding the second semiconductor region, the third semiconductor region provided between the first semiconductor region and the first plane, the third semiconductor region being in contact with the first plane, the third semiconductor region including a first region, a second region, and a third region, the second region being further away from the second semiconductor region than the first region, the third region being further away from the second semiconductor region than the second region; wherein, the second semiconductor region and the third semiconductor region are disposed in a termination region surrounding an active region of the semiconductor device, the third semiconductor region adjoins the second semiconductor region, the second region adjoins the first region, the third region adjoins the second region, an amount of second-conductivity-type impurities at an arbitrary position in the first region, the second region, and the third region is less than an amount of second-conductivity-type impurities at an arbitrary position in the second semiconductor region, an amount of second-conductivity-type impurities in at least a portion of the first region is less than an amount of second-conductivity-type impurities in at least a portion of the second region, an amount of second-conductivity-type impurities in at least a portion of the third region is less than an amount of second-conductivity-type impurities in at least a portion of the second region, and the amount of second-conductivity-type impurities means an integrated value of the amount of second-conductivity-type impurities in a depth direction at a specific position; the device being characterised in that it comprises a fourth semiconductor region of the first conductivity type provided between the first region and the first semiconductor region, the fourth semiconductor region having a higher first-conductivity-type impurity concentration than the first semiconductor region.