A light-emitting diode element, comprising: a first semiconductor layer of a first conductivity type having a principal surface and a rear surface, the first semiconductor layer being made of a gallium nitride-based compound, the principal surface being an m -plane; a semiconductor multilayer structure provided on a first region of the principal surface of the first semiconductor layer, the semiconductor multilayer structure including a second semiconductor layer of a second conductivity type and an active layer interposed between the first semiconductor layer and the second semiconductor layer; a first electrode provided on the second semiconductor layer; a conductor portion provided on a second region of the principal surface of the first semiconductor layer, the conductor portion being in contact with an inner wall of a through hole penetrating through the first semiconductor layer; and a second electrode provided on the second region of the principal surface of the first semiconductor layer, the second electrode being in contact with the conductor portion, characterized in that part of a lateral surface of the inner wall of the through hole is a + c- plane, and another part of the lateral surface of the inner wall of the through hole is a - c -plane; the + c -plane at the lateral surface of the inner wall is provided at a position which is closer to the active layer than the - c -plane at the lateral surface of the inner wall; and/or a lateral surface of the inner wall of the through hole includes two opposite a -planes and a + c -plane and a - c -plane which are opposite to each other; and when viewed in a direction perpendicular to the principal surface of the first semiconductor layer, the active layer has a side corresponding to a side defined by one of the two a -planes, a side corresponding to a side defined by the other one of the two a -planes, and a side corresponding to a side defined by the + c -plane, but does not have a side corresponding to a side defined by the - c -plane. a first semiconductor layer of a first conductivity type having a principal surface and a rear surface, the first semiconductor layer being made of a gallium nitride-based compound, the principal surface being an m -plane; a semiconductor multilayer structure provided on a first region of the principal surface of the first semiconductor layer, the semiconductor multilayer structure including a second semiconductor layer of a second conductivity type and an active layer interposed between the first semiconductor layer and the second semiconductor layer; a first electrode provided on the second semiconductor layer; a conductor portion provided on a second region of the principal surface of the first semiconductor layer, the conductor portion being in contact with an inner wall of a through hole penetrating through the first semiconductor layer; and a second electrode provided on the second region of the principal surface of the first semiconductor layer, the second electrode being in contact with the conductor portion, characterized in that part of a lateral surface of the inner wall of the through hole is a + c- plane, and another part of the lateral surface of the inner wall of the through hole is a - c -plane; the + c -plane at the lateral surface of the inner wall is provided at a position which is closer to the active layer than the - c -plane at the lateral surface of the inner wall; and/or a lateral surface of the inner wall of the through hole includes two opposite a -planes and a + c -plane and a - c -plane which are opposite to each other; and when viewed in a direction perpendicular to the principal surface of the first semiconductor layer, the active layer has a side corresponding to a side defined by one of the two a -planes, a side corresponding to a side defined by the other one of the two a -planes, and a side corresponding to a side defined by the + c -plane, but does not have a side corresponding to a side defined by the - c -plane.