A control device and method for a fuel cell system accurately learns output characteristics of fuel cell even when the output characteristics of fuel cell change due to changes in fuel cell temperature. A lower structure having lower support structures and a lower electrically conductive element is provided. 5 as defined by the coefficient of friction test set forth herein. The detector arrangement generates torques arising in two opposite directions in a measuring plane in response to deviations from a stable load position. The magnet portion includes a permanent magnet having an inner peripheral shape that aligns with an outer periphery of the cylinder; and a ring member formed from a magnetic material and disposed on an outer peripheral side of the permanent magnet.