A micro tubular SOFC (Solid Oxide Fuel Cell) bundle (cube) whose volume is 1 cm³ was fabricated using a newly-developed advanced ceramic processing technology. The cube consists of micro tubular SOFCs and cathode matrices which act as a current collector and provide gas flow paths for air. The performance of the cube was shown to be over 2 W at 550 ^oC with H₂ fuel. Currently, a fabrication technology of micro SOFC stacks by integrating these cubes is under development, aimed for the output performance of several W to kW scale with quick start-up/shut-down performance. They are expected to be applied to portable power sources, APU units for automobiles.