A gripping mechanism includes a holder, a gripping roller, and a downward pushing section. The holder houses the gripping roller. The downward pushing section pushes downward on an object gripped between the holder and the gripping roller. Preferably, the downward pushing section has a first downward pushing mechanism, a second downward pushing mechanism, and a third downward pushing mechanism. The first downward pushing mechanism protrudes from a ceiling surface among inner surfaces of the holder. The second downward pushing mechanism and the third downward pushing mechanism protrude from respective surfaces opposite to the object among outer surfaces of the holder.