Mesoscale eddies are swirling motions with a radius ranging from several tens to a hundred of kilometers. The mesoscale eddies can cause strong vertical displacement of isopycnals, yet the vertical structure of such displacement has not been well understood. This study examines the vertical structures of mesoscale eddies in the Kuroshio-Oyashio Extension region based on the observational and reanalysis datasets. Mesoscale eddies with three distinct kinds of vertical structures are identified.