Abstract: A method of manufacturing a semiconductor element includes forming a mask on a front surface of a substrate, the mask having an opening to expose the front surface; growing a first semiconductor layer by epitaxially growing a semiconductor along the mask, starting from the front surface exposed through the opening, and growing a second semiconductor layer on a surface of the first semiconductor layer located opposite to the substrate in a layering direction, and providing an electrode on a surface of the second semiconductor layer located opposite to the surface of the first semiconductor layer in the layering direction. A width from an end portion of the surface to the electrode is smaller than a width of the mask.