The present invention provides an ultrasonic flow meter unit which can eliminate design factors associated with measuring performance, and improve general versatility and diversity. An ultrasonic flow meter unit of the present invention comprises a measurement fluid passage through which a fluid flows; a pair of ultrasonic transducers provided on the measurement fluid passage; and a measuring circuit board which measures a propagation time of an ultrasonic signal transmitted and received between the ultrasonic transducers, and calculates a fluid flow, lead pins bent with a predetermined angle are connected to terminals of the ultrasonic transducers, and the measuring circuit board is on-board mounted to the measurement fluid passage, and then the lead pins are connected to the measuring circuit board.