Abstract: A method and apparatus for generating plasma in a liquid. The apparatus includes an ultrasonic wave generator for generating bubbles in the liquid, and an electromagnetic wave generator for continuously irradiating electromagnetic waves to the liquid from within the liquid in order to generate plasma. The method of generating plasma in a liquid includes the steps of generating bubbles in the liquid by irradiating ultrasonic waves in the liquid, and generating plasma in the bubbles by continuously irradiating electromagnetic waves from within the liquid to the bubbles.

Abstract: A submerged plasma generator comprising bubble forming means for forming bubbles in a liquid and an electro-magnetic wave generator for radiating electromagnetic waves in a liquid, wherein plasma is generated by, while forming bubbles in a liquid, irradiating the bubbles with electromagnetic waves so that plasma which has high energy but is macroscopically of low temperature and which is safe and is easy to handle can be realized. The submerged plasma generator can be used in, for example, the formation of a film on a substrate and the decomposition of toxic substances such as dioxin.