An ultrasonic current meter having a small size and a small power consumption. A burst signal generation block (110) generates two burst signals having a phase difference, which are transmitted to a pair of ultrasonic probes (6, 7) for transmission/reception. The pair of ultrasonic probes (6, 7) for transmission/reception receives the burst signal, converts the burst signal, and transmits ultrasonic waves having a phase difference into a fluid (9) to be measured. One of the ultrasonic probes receives an ultrasonic wave which has been transmitted from the other ultrasonic probe and has propagated through the fluid and converts the ultrasonic wave into a reception signal. This reception signal is binarized by binarization circuits (16, 17) and subjected to exclusive−OR in an exclusive−OR circuit (30) so as to obtain a phase difference signal expressing a phase difference. The fluid velocity is measured in accordance with this phase difference signal.
