A suction cup, including a bowl-shaped framework, a cup body covering the framework, a connecting rod on a back surface of the framework and passing through the cup body, a bowl-shaped cup cover placed on the connection rod and covering the back surface of the cup body, and an annular protruding rib placed on the periphery of the back surface of the framework, which is in direct contact with the inner surface of the cup cover for effectively transfer the pressing force to make the suction cup less likely to fall off from the supporting surface.