There is provided an ultrasonic signal processing apparatus in which the amount of an ultrasonic propagation material in a measurement unit that stores a transducer array is reduced while the transducer array and a target are separated from each other, and thus maintenance of the ultrasonic propagation material is easily managed.The ultrasonic signal processing apparatus includes a water tank having an opening portion, a measurement unit, and a moving unit. The measurement unit which is disposed on an outside of the water tank, includes a transducer array that transmits and receives an ultrasonic signal, and a space which is filled with a material for propagating the ultrasonic signal, and measures the ultrasonic signal. The moving unit is connected to the measurement unit, and moves the measurement unit between the opening portion and the bottom portion of the water tank, along a side wall thereof.
