Abstract: A mobile infusion pump is used for the constant delivery of a fluid medium. The infusion pump comprises a balloon body for receiving the medium as well as a filling unit and a delivery unit that are in a fluid connection with the balloon body for filling the medium into the balloon body and delivering the medium from the balloon body to a patient. A throttling unit defines a delivery flow rate of the medium. By means of a plurality of continuous longitudinal ribs arranged on a part of the balloon body configured as a tube body, the expansion behavior of the balloon body is improved.