[Problem] The problem to be addressed by the present invention is to provide a device for preventing aquatic organisms from jumping out of an aquarium without directly touching the aquatic organisms, whereby the problem can be resolved or reduced. [Solution] A device for preventing aquatic organisms from jumping out, the device comprising an electrode part installed in the inner periphery of an aquarium for keeping aquatic organisms, and a power supply part electrically connected to the electrode part and applying an electric pulse to the electrode part, wherein the electrode part extends in the horizontal direction around a part or all of the inner periphery of the aquarium, is disposed at a prescribed water dept region within the aquarium, and applies the electric pulse to the electrode part.