A flow meter for measuring the flow rate of a flowing medium has a plastic measurement tube for routing the medium and a connecting device for connecting an end of the measurement tube to an end of a plastic pipeline. So that measurement tube of plastic can be connected easily and to the plastic pipeline, the connecting device is formed by a heating means that is integrated into an inner wall of the end of the measurement tube and that melts at least the end of the measurement tube to thereby form a melted connection between the measurement tube and the pipeline.