The electronic states of Si(111), (110), and (100) surfaces in the early oxidation stages are examined using high‐resolution photoelectron spectroscopy (&Dgr;E<0.3 eV) with synchrotron radiation. The experimental results reveal stronger intensities of Si3+and Si4+oxide components for the Si(111) surface oxidation than for the Si(110) and (100) surface oxidations. Additionally, the depth distribution of intermediary components (SiOx: 0<x≤2) obtained from the tunability of synchrotron radiation shows that the Si3+and Si4+oxidation states form at the first and second outermost layers of the Si(111) surface. Features of the oxidation process are also discussed.