From Stephania iaoonica u collected in Kagoshima Prefecture, We have isolated four new hasubanan alkaloids, stephamiersine (L), epistephamiersine(i), oxostephamiersine (i), and stephasunoline (41, and here we wish to report on the courses of structure elucidation of the bases. On the basis of the results stated above, the structures of stephamiersine (L), epistephamiersine(z), oxostephamiersine (z), and stephasunoline (4) were assigned as drawn in the formulae including their absolute stereochemistry.