  In order to explain weak gravitation in our 4-dimensional universe, a
6-dimensional model with a small extra 2D sphere is proposed. The traceless
energy-momentum tensor is quite naturally appeared in our 6-dimensional model.
The warp factor is given by $\phi (\theta ) = \epsilon + \sin{\theta }$, where
$\epsilon $ plays a role of killing the singular point $\phi (\theta )=0$, and
is assumed $0 < \epsilon \ll 1$. Any massive particle is rolling down into
points along this geodesic line. The light ray can be shown to stay in our
4-dimensional universe. This suggest us that our 4-dimensional world can be
located at $\theta =0 $ and/or $\theta = \pi $, its background metric being
$\epsilon ^2 \eta _{\mu \nu }$. As a result, we have the 4-dimensional Newton
constant, which is given by $G_N \simeq G_6 \epsilon ^{10}$ and the fifth force
coefficients appeared here are $\alpha _i\simeq \epsilon ^{2(i-4)}$, $i=1, 2,
3$. Here $G_6$ is the gravitational constant in 6-dimensional spacetime. If we
take $\epsilon = 10^{-3.8}$ against $G_6\sim 1($GeV$)^{-2}$, we get $G_N\sim
10^{-38}($Gev$)^{-2}$, the present time gravitational constant.
