An apparatus on which a fan can be mounted, including a casing; a plurality of cooling fan units arranged in line on a lower portion of the casing and capable of being inserted into and removed from the casing on an individual basis; and a plurality of plate members disposed above the line in which the cooling fan units are arranged and above a gap between the cooling fan units, the plate members extending in a direction to which an upper surface of each of the cooling fan units is substantially perpendicular and in which the cooling fan unit is inserted into and removed from the casing, wherein each of the plate members is supported so as to be able to pivot about its lower end portion toward both directions.