A beta gauge system was designed and fabricated for a fabric density measurement with high sensitivity in real time. An ionization chamber and 3.7GBq (85)Kr was chosen as a beta radiation sensor and a beta source. An ionization chamber, which had a 0.5microm-thick aluminized mylar film as an incident window, was constructed with a guard electrode structure in consideration of minimizing leakage currents. Xe gas was chosen as a filling gas to increase sensitivity of an ionization chamber. Linearity of the ionization currents against the densities was 0.9894 in the selected measurement range. And the deviation of the ionization currents at a standard density was below 0.02%. The ranges of the density measurement and the active area were from 20 to 999g/cm(2) with +/-1% accuracy and 40mm diameters. The fabricated beta gauge system can be applied to fields such as in the paper, film, and plastic production industries.