  We have set a new upper limit on the stochastic gravitational wave background
(SGWB) using two prototype Torsion-bar Antennas (TOBAs). TOBA is a
low-frequency gravitational-wave detector with bar-shaped test masses rotated
by the tidal force of gravitational waves. As a result of simultaneous 7-hour
observations with TOBAs in Tokyo and Kyoto in Japan, our upper limit with a
confidence level of 95% is $\Omega_{\rm gw}h_0^2 < 1.9 \times 10^{17}$ at 0.035
- 0.830 Hz, where $h_{0}$ is the Hubble constant in units of 100 km/s/Mpc and
$\Omega_{\rm gw}$ is the gravitational wave energy density per logarithmic
frequency interval in units of the closure density. We successfully updated the
upper limit and extended the explored frequency band.
