Provided is a α-Ga2O3 based semiconductor film which is a semiconductor film in a circular shape having a crystal having a corundum-type crystal structure composed of α-Ga2O3 or an α-Ga2O3 solid solution as a main phase. The maximum value θmax and the minimum value θmin for off-angles at the center point X and four outer circumferential points A, B, C, and D of a surface of the semiconductor film satisfy the relationship of θmax-θmin≤0.30°. The off-angle is defined as an inclination angle θ of a crystal axis oriented in the substantially normal direction of the semiconductor film with respect to the film surface normal of the semiconductor film.