Abstract: An ultrasonic aerosol apparatus having a piezoelectric element which generates ultrasonic signals in response to signals received from an oscillating circuit, where the temperature of the piezoelectric element is controlled by an electronic device such as an N.T.C. thermistor. The temperature control device senses the temperature of the piezoelectric element and controls the power fed to the oscillator circuit in accordance with the temperature of the piezoelectric element. Rather than cut power completely to the oscillator circuit (thereby interrupting the atomization process of the apparatus), the temperature control device reduces power fed to the oscillator circuit when the piezoelectric element temperature rises above a predetermined value, and increases power fed to the oscillator circuit when the piezoelectric element temperature falls below a predetermined value. Leakage of liquids (e.g.