A fuel cell stack includes a stack body formed by stacking a plurality of power generation cells. The mounting board includes a metal-made base board, and an insulating board laminated on the base board and formed with a window hole extending therethrough which is larger than the outer periphery of the light emitting element. The invention also relates to a sintering powder for producing the sliding bearing material, a sliding bearing composite material having a steel protective layer and a bearing layer composed of such a sintered-on sliding bearing material. The light detectors also detect a synchronization pulse from each transmitter that is emitted once per revolution. Configuration information for the host is automatically changed to include the association between the LUN and the target.