The present invention is a Solid Oxide Fuel Cell Reforming Power System that utilizes adiabatic reforming of reformate within this system. The gravity doesn’t affect the control force of the optical head in the horizontal operation type, reduces the control force in a vertical operation type, and increases the control force in inverse operation type. The retainer ring includes a first member made of a magnetic material and a second member having a magnet disposed on a surface thereof which is held in abutment against the first member.