This study was to investigate for comparison between single rating and average ratings from multiple presentations of the same stimulus for measuring the voice quality of dysphonia using 7-point equal-appearing interval (EAI) rating scale. Overall severity of voice quality for 46 /a/ vowel stimuli (23 stimuli from dysphonia, 23 stimuli from control) was rated by 3 experienced speech-language pathologists (averaged 19 years; range = 7 to 40 years). For average ratings, each stimulus was rated five times in random order and averaged from two to five times. Although higher inter-rater reliability was found in average ratings than in single rating, there were no significant differences in rating scores between single and multiple average ratings judged by experienced listeners, suggesting that auditory perceptual ratings judged by well-trained listeners have relatively good agreement with the same stimulus across the judgment. Larger variations in perceptual ratings were observed for moderate voices than for mild or severe voices, even in the average ratings.