A new inoceramid species (Inoceramus nakagawensis sp. nov.) from the Upper Cretaceous Yezo Supergroup, Hokkaido, Japan, is reported and systematically described in detail. The shell sculpture of I. nakagawensis sp. nov. is characterized by very fine, distinct, and regular to somewhat irregular concentric rings. Its occurrence is probably restricted to the upper Lower to lower Middle Turonian, making it a short-ranging species. The present species would be closely allied to Inoceramus cuvieri Sowerby, 1814, from the middle to upper Turonian Stage of Far East Russia.