The power consumption, gas dispersion, and mass transfer volumetric coefficients are investigated in a gas-liquid agitated vessel with a disk turbine for various geometries, positions of the sparger, and directions of gas discharge. A sparger larger than the impeller is effective for obtaining high aeration power consumption and a high mass transfer volumetric coefficient. When the sparger is used, the flooding phenomenon does not occur easily. The gas is sufficiently dispersed when the large sparger is used, even if the gas is not blown directly into the impeller.