A photoelectric conversion device includes a circuit board, light-emitting modules, light-receiving modules, an optical coupling module, and a protecting member. The light-emitting modules and the light-receiving modules are mounted on the circuit board. The optical coupling module is mounted on the circuit board, and includes first and second optical surfaces, a reflection surface, first converging lenses formed on the first optical surface and corresponding to the light-emitting modules and the light-receiving modules, and second converging lenses formed on the second optical surface and corresponding to the first converging lenses. The protecting member is mounted on the circuit board to shield the optical coupling module, the light-emitting modules, and the light-receiving modules, and only exposes the second converging lenses.