  We theoretically study a possible topological superconductivity in the
interacting two layers of Rashba systems, which can be fabricated by the
hetero-structures of semiconductors and oxides. The hybridization, which
induces the gap in the single particle dispersion, and the electron-electron
interaction between the two layers leads to the novel phase diagram of the
superconductivity. It is found that the topological superconductivity {\it
without breaking time-reversal symmetry} is realized when (i) the Fermi energy
is within the hybridization gap, and (ii) the inter-layer interaction is
repulsive, both of which can be satisfied in realistic systems. Edge channels
are studied in a tight-binding model numerically, and the several predictions
on experiments are also given.
