A web advertising effectiveness measuring apparatus measures a viewing time period of an advertisement on a web page displayed on a display device of a user terminal, the apparatus includes: a device for acquiring window information including a location and a size of a window in which the web page is displayed; an device for acquiring advertisement information including a location and a size of the advertisement; a device for acquiring a display area of the advertisement; a device for taking images of a user; an device for detecting an eye direction of the user based on the images; a device for making a determination whether the advertisement is on a visual line of the user; a device for measuring the viewing time period based on the determination; and a device for linking and storing the viewing time period and the advertisement information.