This article describes a novel hollow-core THz waveguide composed of ten 134 μm diameter silica capillaries with a 6mm diameter hollow-core structure. The attenuation coefficient of the h11 mode in a 400 GHz transmission window from 0.89 to 1.29 THz was calculated to be below 0.5 dB/m, which is about 8000 times lower than that of silica. A 1-meter long waveguide was fabricated and characterized from 0.75 to 1.10 GHz, and measured propagation loss was as low as 0.5 dB/m at 1.05 THz. Long-length silica-based THz waveguide enables new harsh environment applications for gas/vapor interaction to enhance THz wave behavior and extend THz spectroscopy capabilities.