In our daily lives, we often use onomatopoeia to convey images of products. However, the correspondence between onomatopoeia and physical quantities is not clear. To apply onomatopoeia to product design, we focused on the relationship between the sound symbolism of onomatopoeia and product sound quality. The target of the evaluation was the operation sound of the rotary switch. A subjective evaluation experiment was conducted in which participants were asked to free answer to the impressions associated with the operation sounds using onomatopoeic expressions. The obtained onomatopoeia was then analyzed by quantitative text analysis using mora as the unit of analysis. The results showed the voiced consonants appeared more frequently in the louder operation sounds. In addition, the vowel /o/ appeared more frequently in sounds with low sharpness, and the vowel /i/ appeared more frequently in sounds with high sharpness. Since these trends are similar to other studies on sound symbolism, this study shows the possibility of using onomatopoeia in product design by utilizing sound symbolism.