The abundance of oxygen was determined for selected very metal-poor G-K stars (six giants and one turn-off star) based on the high S/N and high-resolution spectra observed with the Keck HIRES in the red through near-IR region comprising the permitted O i lines (7771-5, 8446) along with the [O i] forbidden line at 6363 Å. It turned out that both the abundances from the permitted line features, O i 7771-5 and O i 8446, agree quite well with each other, while the forbidden line yields somewhat discrepant and divergent abundances with a tendency of being underestimated on the average. The former (7773/8446) solution, which we believe to be more reliable, gives a fairly tight [O/Fe] vs. [Fe/H] relation such that increasing steadily from [O/Fe]~0.6 (at [Fe/H]~-1.5) to [O/Fe]~1.0 (at [Fe/H]~-3.0) is reasonably consistent with the trend recently reported based on the analysis of the UV OH lines.