A DC-magnetron inline sputter was established, and the influence of the base pressure on the structural characteristics of the ITO thin films was studied. When the inline sputter system was established and operated for ITO sputtering, its initial vacuum level did not go below $5 imes10^{-6}$ torr. The vacuum leak test was conducted by measuring t he elapsed time until the vacuum level reached $1 imes10^{-6}$ torr. The base pressure was successfully maintained at $1 imes10^{-6}$ torr for 900 min, and the uniformity of the ITO film that had been deposited at this pressure significantly improved.