To provide a submerged plasma generating device for efficiently generating plasma by electric discharge in the liquid to be processed even when using at a large scale treatment facility as seen in a waste liquid treatment field site.

The submerged plasma generating device, which generates plasma in the liquid, includes: a main pipe (10); an air supply pipe (102) for supplying a gas to the main pipe (10); a closed body (12) closing an opening part of the main pipe (10) and formed with porous materials for discharging a gas passed through the main pipe (10) into the liquid as microbubbles; and a wire electrode (20) whose tip end part (22) is located in a space (120) formed by the main pipe (10) and the closed body (12) and provided close to the closed body (12).