A sheet storage device includes a housing, a sheet stacking tray, a shaft, a suspension mechanism, a driving device, and a drive transmission portion. The suspension mechanism includes a plurality of winding pulleys and a plurality of wires. The drive transmission portion includes a plurality of driving gears and a plurality of driven gears. The plurality of winding pulleys permit the engagement positions of the plurality of driven gears with respect to the plurality of driving gears to be changed in the circumferential direction of the shaft. The drive transmission portion changes the respective engagement positions of the plurality of driven gears and thereby changes the respective relative positions of the fixing portions of the plurality of winding pulleys in the rotation direction. This permits adjustment of the respective unwound lengths of the plurality of wires.