A specimen of the unknown form of Octopus species was collected from Onsan, Kyungsangnam-do, eastern coast of Korea on 20th June 2004 with a bottom trawl. The specimen distinguished from the other Octopus species reported hitherto by its extremely short 2nd pair of arm and hectocotilization of the right 4th arm. It may be described, therefore, as new species, but only one specimen was collected unfortunately. A new name will be deferred, consequently, until more specimens will be available in the future.