Questionnaire surveys were conducted to evaluate the economic value of sound quality of vacuum cleaners and hairdryers using the contingent valuation method. In the experiment for each machine, two stimuli inducing the unpleasant and pleasant impressions were presented to subjects based on the assumption that the former sound was emitted from the original product and the latter from the product with improved sound quality. Subjects were asked how much extra they would pay for the improved product in addition to the price of the original product. The questionnaire also sought personal attributes of each subject such as age, annual income, points checked when buying products : performance, price, etc. Logistic regression analysis was applied to the obtained results. Consequently, the prices for the improvement of sound quality were estimated as being 3026 Japanese yen for vacuum cleaner, and 469 Japanese yen for hairdryer, which are equivalent to 12% of the original price of each machine.