A high-low intensity focused ultrasound treatment apparatus according to the present disclosure includes a plurality of ultrasound sources, and a controller to control a center frequency and intensity of focused ultrasound outputted from the ultrasound sources, wherein each of the ultrasound sources includes a first ultrasound transducer to output low-intensity focused ultrasound to detect a lesion, and a second ultrasound transducer to output high-intensity focused ultrasound to ablate or remove the detected lesion. The low-intensity focused ultrasound outputted from the first transducer may be used to detect a lesion in a patient's brain by applying a stimulus to the brain, and at the same time, investigating a response, and the high-intensity focused ultrasound outputted from the second transducer may be used to ablate or remove the detected lesion by applying a thermal or mechanical stimulus to the lesion.