A suction cup includes a suction cup main body, an attachment surface and a gel layer. The surface of the gel layer serves as a suction surface. In a method of manufacturing a suction cup, a cavity is formed in the inside of a common mold and a primary mold. Next, a synthetic resin material is injected into the cavity, to mold the suction cup main body. Subsequently, the primary mold is opened, to obtain the suction cup main body. Next, a secondary mold is mated to the common mold, whereby a cavity is formed in the inside of the common mold and the secondary mold. Subsequently, a gel is injected into the cavity, to mold the gel layer. Next, the secondary mold is opened, to obtain a suction cup composed of the gel layer and the suction cup main body, on the common mold.