An ultrasonic sensor unit includes an ultrasonic transmission sensor array having a plurality of ultrasonic transmission sensors configured and arranged to transmit ultrasonic waves, and an ultrasonic reception sensor array having a plurality of ultrasonic reception sensors configured and arranged to receive the ultrasonic waves. The ultrasonic reception sensor array re coupled to the ultrasonic transmission sensor array so that the ultrasonic transmission sensors and the ultrasonic reception sensors do not overlap in planar view. One of the ultrasonic transmission sensor array and the ultrasonic reception sensor array include a plurality of through-holes through which one of the ultrasonic transmission sensors and the ultrasonic reception sensors provided in the other of the ultrasonic transmission sensor array and the ultrasonic reception sensor array are exposed.