A solenoid valve is described, its armature having a part that is slidingly displaceable on the foundation bolt and is movable between two stops of the foundation bolt against the tension force of a restoring spring. A spindle projects from the transmission housing. When the user actually accesses the recording medium, the prescribed area is accessed. The main material comprises the layers of panel portion and the first and second side gusset portions continuing longitudinally thereof respectively, the feeding means feeding the main material longitudinally of the layers of panel portion and the first and second side gusset portions. A body bias can be applied to a first set of NAND strings for which operations are being performed by controlling a first voltage provided to a source side of the first set of NAND strings and a second voltage provided to a p-well. The photoelectric transducer element array has a common conductive layer, and the photoelectric transducer elements are mounted on the common conductive layer in alignment with entrance or exit ends of the optical waveguide.