A screw fall preventing structure prevents a screw from falling out of a unit that is attachable to and removable from a main body of an apparatus. The screw is used for fastening the unit to the main body of the apparatus. The screw fall preventing structure includes: a wire piece having a bent portion fitted around the screw to hold the screw axially rotatably; and a fixing member fixing the wire piece to the unit. When the unit is not fastening by the screw, the screw is elastically supported via the wire piece on the fixing member and the elasticity is given by a portion of the wire between a portion fixed by the fixing member and the bent portion.