To provide an oxide semiconductor film which has high stability and does not easily cause variation in electric characteristics of a transistor, a transistor including the oxide semiconductor film in its channel formation region, and a highly reliable semiconductor device including the transistor. The oxide semiconductor film including indium includes a crystal part whose c-axis is substantially perpendicular to a surface of the oxide semiconductor film. In the crystal part, the length of a crystal arrangement part containing indium and oxygen on a plane perpendicular to the c-axis is more than 1.5 nm. Further, the semiconductor device includes the transistor including the oxide semiconductor film in its channel formation region.