As IT grows, Web advertisement continues to grow. The cost of Web advertising media in Japan reached 1,220.6 billion yen in 2017. This was 23.6% of the total advertising expenditure. On the other hand, the more involved a product is, the less likely a consumer is to purchase it impulsively due to an advertisement. Those who spontaneously search for information can be expected have similar purchasing behavior. However, there are few examples that quantitatively validate that theory. Therefore, focusing on the Japanese automobile industry, we validated the difference in purchasing behavior (estimation of price on the web) between customers induced by Web advertisement and customers who voluntarily searched for information.