A semiconductor device with a lateral element includes a semiconductor substrate, first and second electrodes on the substrate, and a resistive field plate extending from the first electrode to the second electrode. The lateral element passes a current between the first and second electrodes. A voltage applied to the second electrode is less than a voltage applied to the first electrode. The resistive field plate has a first end portion and a second end portion opposite to the first end portion. The second end portion is located closer to the second electrode than the first end portion. An impurity concentration in the second end portion is equal to or greater than 1×1018 cm−3.