We proposed a thin piezoelectric cantilever to measure an airflow velocity change. An airflow sensor using a PZT cantilever and a flow channel was fabricated. We measured the relationship between the airflow velocity change and the piezoelectric voltage of the cantilever. The dimensions of the sensor and the cantilever are 25 mm × 20 mm × 20 mm and 1500 μm × 1000 μm × 2 μm respectively. We evaluated the effect of the diameter of the flow channel on the sensor response. It was demonstrated that the fabricated sensor generated an output voltage of several millivolts when the airflow velocity changed at a rate of approximately 1 m/s. It was observed that the output voltage increased as the diameter of the flow channel became small.