Anglerfish Lophius litulon (Jordan) caught commercially in the East China Sea off western Japan were found to be infected with the chondracanthid copepod Acanthochondria spirigera Shiino, 1955. Lophius litulon is a new host for this copepod. We made an observation on the occurrence of A. spirigera on anglerfish because the copepods of the genus Acanthochondria cause food hygiene problems at fish markets in Japan. Overall prevalence of infection with A. spirigera was high (71% of 31 fish examined), and one or two copepods were usually found on an infected fish. Their attachment site was the roof and floor of the buccal cavity of the fish. The number of copepods per fish showed an increasing tread with fish size and during the fall months (September to November).