Two species of Euthiconus Reitter were previously known to occur in the Palaearctic region, distributed in Europe (E. conicicollis (Fairmaire Laboulbène)) and in the Russian Far East (E. lustrificus Kurbatov). A description of the first Japanese species, Euthiconus nopporoensis sp. n., is given, based on specimens collected on Hokkaido. The new species shares with E. lustrificus unmodified male protrochanters and a similar shape of the pronotum; it differs in a bottle-shaped aedeagus, sparser setae on the pronotum, and a shorter antennomere III. Key morphological structures of all Palaearctic species of Euthiconus are illustrated, to facilitate identifications.