In recent years, extermination work has been carried out due to the increase in the number of jellyfish. In this research, we design and develop an AUV (Autonomous Underwater Vehicle) and conduct a jellyfish crushing experiment for the purpose of automating jellyfish extermination work. In the design and development of an AUV, electronic parts to operate autonomously were selected, and each electronic part was placed inside the hull to create a system diagram of them. Regarding the jellyfish extermination device, we designed and developed a device that sucks and crushes jellyfish together with water from the suction port. In this experiment, a jellyfish extermination device was mounted on developed AUV, and a crushing experiment was conducted using a jellyfish sample which is made by water and gelatin. As a result, it was confirmed that a jellyfish sample with a diameter of about 7 cm and a height of about 11 cm could be crushed to small pieces, which has average of volume 2885.6 mm³, during less in about 8 seconds.