We propose a vowel generation method focused on outline of frequency spectrum for a vowel.One of some vowels is sampled, and modifying it according to the feature of frequency spectrum foreach vowel. In this way, the feature of tone is kept and other four vowels are generated from onevowel. We have experimented the case of other four vowels were generated from each of vowels /a/, /i/, /u/,/e/, /o/, and evaluated for fi ve vowels obtained by the above method by four test subjects. We obtained good results in the experiment that vowels of /a/, /i/, /u/, and /o/ are generated by modifi ed vowel /e/ .