Provided are an ultrasonic beauty instrument, a voltage application method, and an ultrasonic head, whereby a plurality of types of treatments can be performed by a single device through use of an ultrasonic vibrator for vibrating in a primary vibration mode and a vibration mode other than the primary vibration mode. In the present invention, an ultrasonic head is used in which the vibration power at a second natural frequency is at least 30% of the vibration power at a first natural frequency, an oscillator is configured having a first oscillation mode for causing the ultrasonic head to vibrate at the first natural frequency and a second oscillation mode for causing the ultrasonic head to vibrate at the second natural frequency, and it is possible to switch to one of the first or second oscillation mode.提供藉由以1次振動模式及該1次振動模式以外的振動模式進行振動的超音波振動子,可以單一裝置進行複數種類的護理的超音波美容器具、電壓施加方法及超音波頭。以超音波頭而言,使用以第2固有振動數的振動的功率為以第1固有振動數的振動的功率的至少30%以上者,並且振盪器形成為具有:以前述第1固有振動數使前述超音波頭振動的第1振盪模式、及以前述第2固有振動數使前述超音波頭振動的第2振盪模式者,可切換成前述第1或第2振盪模式的其中一者。
