There is a need to develop new energy sources that can replace or complement renewable energies such as solar power generation and wind power generation, which have been put into practical use but have many problems in terms of economy and stability. The author has focused on the SMFC (Sediment Microbial Fuel Cell) power generation research as one solution to this problem. In particular, the control of microorganisms that are the source of power generation was examined to increase the electrical output, which is the key to practical application. By incorporating an inorganic porous structure into the fuel cell, the author has succeeded in accumulating microorganisms near the electrode for the first time. As a result, it was found that the output characteristics of the SMFC were remarkably improved by inserting the porous material, which was embedded in the soil in advance and promoted the accumulation of microorganisms and organic substances, in the vicinity of the anode. By improving the open-circuit voltage and the short-circuit current, the output power has increased about 6 times on average compared to the conventional one. It is considered that the reason for this is that the accumulation of microorganisms near the anode promotes electron charge transfer into the electrode, increases the amount of generated hydrogen ions, and accelerates the reduction reaction. Furthermore, the author tried to optimize the amount and arrangement of the inorganic porous material to be inserted, and to introduce iron ions that have the function of promoting electron transfer in the battery. As a result, excellent output characteristics for practical use could be obtained.