AbstractRapid progress in β-gallium oxide (β-Ga₂O₃) material and device technologies has been made in this decade, and its superior material properties based on the very large bandgap of over 4.5 eV have been attracting much attention. β-Ga₂O₃ appears particularly promising for power switching device applications because of its extremely large breakdown electric field and availability of large-diameter, high-quality wafers manufactured from melt-grown bulk single crystals. In this review, after introducing material properties of β-Ga₂O₃ that are important for electronic devices, current status of bulk melt growth, epitaxial thin-film growth, and device processing technologies are introduced. Then, state-of-the-art β-Ga₂O₃ Schottky barrier diodes and field-effect transistors are discussed, mainly focusing on development results of the author’s group.