To provide a suction cup which is simple in detachment, capable of being sucked even on a slightly curved surface, or even a slightly uneven surface by attaching a doughnut-like gel-sheet packing on a suction surface.

A packing 2 formed of a gel sheet is cut in a doughnut shape, and adhered on a suction surface of a suction cup 1 or to an object making use of slight adhesivity of the gel sheet, and the suction cup 1 is fitted in such a manner that the sheet is held between the suction surface and the object. The packing 2 may be adhered on the suction cup 1 at the starting time, or a recess may be provided on a part of the suction surface on which the packing 2 is adhered. When the suction cup 1 is attached, gaps formed between the suction surface and uneven parts on the surface of the object is filled with the packing 2, and no air enters inside. Thus, the suction cup 1 is not detached. The packing 2 may either circular one or an O-ring, and if the packing 2 is too thick, the movement becomes excessive due to its flexibility, and if the packing is too thin, it can not be adapted to unevenness.