An ultrasonic flow meter comprising: a measurement pipe, which has a measurement pipe wall, at least in some parts a basic shape having a rotationally symmetric or polygonal cross-section, and a straight measurement pipe axis; a transmitter for transmitting an acoustic signal on a first signal path; and a receiver for receiving the acoustic signal on the first signal path; The measurement pipe has a plurality of reflection surfaces, by which the acoustic signal on the first signal path is reflected multiple times, and wherein the reflection surfaces are integrally formed from the measurement pipe wall, the reflection surfaces for reflecting the acoustic signal being designed in such a way that one or more of the reflection surfaces at least partially protrude into the basic shape of the measurement pipe and one or more of the reflection surfaces project outward at least from the basic shape of the measurement pipe.