Provided is a semiconductor device for high power application including a novel semiconductor material with high productivity. Alternatively, provided is a semiconductor device having a novel structure in which the novel semiconductor material is used. Provided is a vertical transistor including a channel formation region formed using an oxide semiconductor which has a wider band gap than a silicon semiconductor and is an intrinsic semiconductor or a substantially intrinsic semiconductor with impurities that can serve as electron donors (donors) in the oxide semiconductor removed. The thickness of the oxide semiconductor is greater than or equal to 1 μm, preferably greater than 3 μm, more preferably greater than or equal to 10 μm, and end portions of one of electrodes that are in contact with the oxide semiconductor is placed inside end portions of the oxide semiconductor.