Provided is a method of controlling voltage levels of overall outputs in a combinational mode, in an ultrasonic diagnosis apparatus that may operate in the combinational mode. A judging unit of the ultrasonic diagnosis apparatus may judge whether at least a part of individual modes included in the combinational mode exceeds a threshold determined by safety standards, in accordance with an inputted overall output voltage level control command. When it is judged that at least the part of the individual modes exceeds the threshold determined by the safety standards, an output control unit may maintain an individual output with respect to the at least the part, among the voltage levels that may be outputted from a transducer, to be below the threshold, so that the individual output may be below the standards in accordance with the overall output control command.