  Using a new method recently proposed by the HAL QCD collaboration to study
hadron interactions in lattice QCD, we investigate a possibility for an
existence of the H-dibaryon in the flavor SU(3) symmetric world. A potential
for the flavor-singlet baryon-baryon channel is derived from the
Nambu-Bethe-Salpeter wave function, and the elusive H-dibaryon is shown to be a
bound state, with the binding energy of 20--50 MeV for the pseudo-scalar meson
masses in the range that 469--1171 MeV.
