In recent years, increase in the number of jellyfish causes damage in the fishery and tourism industries. Currently, most of the jellyfish removal work is carried out by workers. However, this conventional removal work is required a lot of time and manpower. In this paper, we proposed a method for removal work of jellyfish using an underwater robot. Also, we introduced developed ROV type underwater robot, which is called JENOS (Jellyfish Extermination Nifty-robot for Ocean Sustentation), and its removal motion performance. The ROV was developed in consideration of the attitude control during the removal operation. Because, the attitude, such as surge and pitch, of ROV became unstable when performing jellyfish removal work. To solve this problem, we equipped 8 thrusters to improve attitude stability during the jellyfish removal work. As results, surge acceleration was reduced about 30.0%, and pitch angle velocity was reduced about 25.8%, and the jellyfish sample was chopped within 25 seconds.