A transistor with a high on-state current and a semiconductor device with high productivity are provided. Included are a first oxide, a second oxide, a third oxide, and a fourth oxide over a first insulator; a first conductor over the third oxide; a second conductor over the fourth oxide; a second insulator over the first conductor; a third insulator over the second conductor; a fifth oxide positioned over the second oxide and between the third oxide and the fourth oxide; a sixth oxide over the fifth oxide; a fourth insulator over the sixth oxide; a third conductor over the fourth insulator; and a fifth insulator over the first insulator to the third insulator. The fifth oxide includes a region in contact with the second oxide to the fourth oxide and the first insulator. The sixth oxide includes a region in contact with the fifth oxide, the first conductor, and the second conductor. The fourth insulator includes a region in contact with at least the sixth oxide, the third conductor, and the fifth insulator.