We describe a simple technique for the realization of a two-dimensional ultrasonic anemometer using a loudspeaker. The ultrasonic anemometer was realized in order to reduce the number of acoustic transducers. Two sound propagation paths were configured by the loudspeaker, a microphone and an acoustic reflector. The number of loudspeakers was reduced to one by using a reflected sound from the acoustic reflector. The propagation path of the reflected sound (reflected path) was tilted at an angle 45 deg from the propagation path of the direct sound (direct path). The reflected path was received at the microphone after reflection at the acoustic reflector. Experiments were performed under winds of 4.0 m/s and 5.5 m/s at the center of the measurement area. The lengths of the direct and the reflected paths were 0.5 m and 0.71 m. The wind velocities were 2.8 m/s and 3.0 m/s, respectively. Results showed that the ultrasonic anemometer measured mean wind velocities in the measurement area.