A device for treating obesity in humans is described, with a balloon arrangement that can be introduced into the human stomach and that can be filled with a fluid and emptied inside the stomach for controlled reduction of the stomach volume; with at least one fluid line, which is connected in a fluid tight manner to the balloon arrangement and via which the balloon arrangement can be filled and emptied transcutaneously; with at least one securing means provided along the fluid line in order to fix the fluid line to skin and tissue layers enclosing the stomach; and with at least one valve unit provided along the fluid line. The balloon arrangement has a first means that can be filled with the fluid and assumes a balloon-like configuration in a filled state, a second fillable means which, in a filled state, assumes a ring-shaped or loop-shaped configuration and radially encloses a clear internal diameter, and the first and second means are connected to each other in so that the first means extends into a first half space via a plane enclosed by the ring-shaped or loop-shaped configuration of the filled second means.