The purpose of this study is to estimate the emotions that users experience when they see advertisements displayed by websites. It is possible to pro-vide users with the products and services they want by displaying web advertisements appropriately. This is a desirable situation for companies, users, and websites. We thought that users would have a physical reaction when they viewed a website. We especially focused on change of pupil size. In our experiment, the subjects were presented several types of web advertisements.The types of web ads presented are: 3 types of ads display methods (banner-ad, front-ad, Click-ignore ad), 2 types of advertising images (positive and negative), for a total of 6 combinations.We found a characteristic response of pupil size by ads types by use of golden cross and dead cross analysis. And we show possibility of estimating emotion by pupil size.