The present disclosure relates to an ultrasound therapy device using high-intensity focused ultrasound (HIFU) and a control method thereof. The ultrasound therapy device comprises: an array type HIFU converter having a plurality of HIFU conversion elements； and a control unit for performing a control to treat tissues in a focusing area by selecting and driving some of the HIFU conversion elements of the array type HIFU converter and irradiating ultrasound signals to an object through the driven active conversion elements to generate heat energy, wherein, after an elapse of a predetermined time period, the control unit drives a combination of other conversion elements as new active conversion elements in replacement of the active conversion elements.
