a first electrode;

a second electrode, a direction from the first electrode to the second electrode being along the first direction;

a first semiconductor region including Al_x1Ga_1−x1N (0≤×1<1), the first semiconductor region including a first partial region, a second partial region, a third partial region, a fourth partial region, a fifth partial region, and a sixth partial region, a direction from the first partial region to the first electrode, a direction from the second partial region to the second electrode, and a direction from the third partial region to the third electrode being along a second direction crossing the first direction, the fourth partial region being between the first partial region and the third partial region in the first direction, the fifth partial region being between the third partial region and the second partial region in the first direction, the sixth partial region being between the fifth partial region and the second partial region in the first direction;

a second semiconductor region including Al_x2Ga_1−x2N (0<×2≥1, ×1<×2), the second semiconductor region including a first semiconductor portion, a second semiconductor portion, and a third semiconductor portion, a direction from the fourth partial regions to the first semiconductor portion being along the second direction;

a first conductive member, the first conductive member being electrically connected with a first one of the first electrode and the third electrode, or the first conductive member being configured to be electrically connected with the first one, the first conductive member including a first conductive end portion in the first direction, a position of the first conductive end portion in the first direction being between the position of the third electrode in the first direction and the position of the second electrode in the first direction; and

an insulating member including a first nitride region and a second nitride region, the second semiconductor portion being between the fifth partial region and the first nitride region in the second direction, the third semiconductor portion being between the sixth partial region and the second nitride region in the second direction, the first nitride region including silicon and nitrogen, the second nitride region including silicon and nitrogen, a first ratio of a concentration of silicon to a concentration of nitrogen in the first nitride region being lower than a second ratio of a concentration of silicon to a concentration of nitrogen in the second nitride region, the first nitride region including a first nitride end portion, the first nitride end portion being in contact with the second semiconductor region, the first nitride end portion facing the second nitride region in the first direction, a positions of the first nitride end portion in the first direction being between a position of the first conductive end portion in the first direction and the position of the second electrode in the first direction.