ULTRASONIC TREATMENT APPARATUS

To improve propagation performance and uniformity of ultrasonic waves more easily, even when treating multiple treatment objects. An ultrasonic treatment apparatus according to the present invention includes: a treatment tank capable of containing a treatment object and a treatment liquid for immersing the treatment object; and an ultrasonic application mechanism that applies ultrasonic waves to the treatment liquid, wherein the treatment tank has a long axis where cross-sectional shapes are substantially identical to each other, and a wall surface to a scheduled liquid level height line of the treatment liquid is formed by a concave surface, and the ultrasonic application mechanism is installed at a position where an angle θ formed by a normal line of an oscillation surface of ultrasonic waves and the scheduled liquid level line of the treatment liquid is 5° to 80°.