To measure an ultrasonic wave even when a flow rate is changed greatly, or when the kind of measuring fluid is changed.
This device is equipped with an output invalidation circuit 10 for controlling a timing for invalidating the output from a receiving circuit 2 corresponding to a propagation time of the ultrasonic wave, and an output invalidation correction circuit 11 for shortening a timing for invalidating the output from the receiving circuit 2 when the propagation time of the ultrasonic wave is changed greatly. Even when the propagation time of the ultrasonic wave is changed greatly and a reception timing becomes earlier and the reception timing is overlapped with an output invalidation period of the receiving circuit 2, the ultrasonic wave can be received by shortening a time for invalidating the output from the receiving circuit 2.
NAKABAYASHI YUJI
Tomoyasu Sakaguchi
Hiroki Naito