Ceramic reactors, which convert materials and energy electrochemically, are expected to solve various environmental problems, and the use of a microreactor design was shown to realize a high performance reactor with high thermal durability, operable at lower temperatures. Our research project, “Advanced Ceramic Reactor,” supported by the New Energy and Industrial Technology Development Organization, targets to develop new fabrication technology for such microreactors and modules using conventional, commercially available materials. In this study, fabrication technology of microtubular ceramic reactors have been investigated for aiming solid oxide fuel cell (SOFC) applications such as small distributed power generators, auxiliary power units for vehicles, and portable power sources. So far, microtubular SOFCs under a diameter of 1 mm using doped ceria electrolyte, and Ni–ceria based cermet for tubular support has been successfully developed and evaluated. The single microtubular SOFC showed a cell performance of (at 0.7 V) at with fuel. The bundle design for such tubular cell was also proposed and fabricated. The discussion will cover the fabrication technology of a single tubular SOFC and bundle, and the optimization of the cell and bundle design by considering gas pressure loss and current collecting loss.