The ultrasonic transmitter/receiver device comprises a transmission section which transmits ultrasonic waves generated by a piezoelectric element when a transmission signal is inputted, a reception section which is superposed directly or indirectly on the transmission section and outputs a reception signal generated by a piezoelectric element when ultrasonic waves are received, a pair of a transmission signal wire and a transmission grounding wire for supplying the transmission signal to the transmission section, and a pair of a reception signal wire and a reception grounding wire for taking the reception signal from the reception section. The transmission grounding wire and the reception grounding wire are used in common as a common grounding wire. The common grounding wire and the transmission signal wire, and further the common grounding wire and the reception signal wire are disposed on different side surfaces of the transmission section and the reception section superposed with each other.
