A new species of salamander, Hynobius mikawaensis, is described from the eastern part of Aichi Prefecture, central Japan. It is a lentic breeder of the so-called H. lichenatus species group, and is phylogenetically closest to H. nigrescens and H. takedai. Morphologically, it differs greatly from H. nigrescens, but is very similar to H. takedai, from which it could be differentiated by some morphological traits such as shorter forelimbs and hindlimbs, but longer axilla-groin length, all relative to snout-vent length. The new species from the southern Pacific side of central Japan is completely separated geographically from H. nigrescens and H. takedai, both from the northern, Japan Sea side, by the intervening high mountains. This north/south disjunctive distributional pattern is highly unique among Japanese fauna. The range of the species is so small that immediate measure of conservation is necessary.