Abstract: Provided is a semiconductor laminate structure including a Ga2O3 substrate and a nitride semiconductor layer with high crystal quality on the Ga2O3 substrate, and also provided is a semiconductor element including this semiconductor laminate structure. In one embodiment, this semiconductor laminate structure includes a ?-Ga2O3 substrate including ?-Ga2O3 crystal and a principal surface inclined from a (?201) surface to a [102] direction nd a nitride semiconductor layer including AlxGayInzN (0?x?1, 0?y?1, 0?z?1, x+y+z=1) crystal formed by epitaxial crystal growth on the principal surface of the ?-Ga2O3 substrate.