The present invention provides a radial foil bearing for supporting a high-speed rotating shaft. The radial foil bearing comprises a top foil (1): a key (2) welded to a cut portion of the top foil; an inner bump coil (3) disposed outwards of the top foil, the inner bump being formed of a wider and higher bump and a narrower and lower bump alternately arranged; an outer bump foil (4) disposed outwards of the inner coil, the outer bump having a height lower the that of the narrower and lower bump of the inner bump foil; a bump sheet (5) for fixing the inner bump and the outer bump; and a bearing housing (6) disposed outwards of the bump sheet and having a key groove (7).