Disclosed herein is a megasonic cleaning module. The megasonic cleaning module includes a vibrator having a piezoelectric element mounted therein for generating ultrasonic waves by the vibration of the piezoelectric element, a first vibratory rod having a diameter gradually decreased to concentrate the longitudinal ultrasonic waves generated from the vibrator, and a second vibratory rod for progressing the longitudinal ultrasonic waves, generated from the first vibratory rod, in the transverse direction. The size of the second vibratory rod at one side thereof where the second vibratory rod is coupled to the first vibratory rod is less than that of the second vibratory rod at the other side thereof, with the result that the longitudinal ultrasonic waves are not prevented from affecting the wafer.