With the aim of improving bacterial cellulose (BC) production in an aerated and agitated culture, the effects of the oxygen and carbon dioxide pressures were investigated. The BC production rate was dependent on the oxygen transfer rate, which declined as the broth viscosity increased, accompanied by BC accumulation. Increasing the partial pressure of oxygen by sparging with oxygen-enriched air and/or raising the operating pressure improved the oxygen supply, while the agitation power required was lowered. Although the BC production rate was not affected by higher oxygen pressure, it was reduced as the operating pressure was raised. The reduction in the production rate was considered to be due to the high carbon dioxide pressure, because carbon dioxide-enriched air also reduced the BC production rate, while the reduction was canceled out by increasing the air flow rate.