Sales from online advertisements have increased, and this market is expected to expand further with the spread of the Internet of Things (IoT). To enable more effective marketing, it is important to consider the advertisement’s design. In general, questionnaires are typically used to evaluate the marketing effectiveness. However, neuromarketing based on brain activity has attracted attention in recent years as a new marketing method. In this study, we examined the effects of advertisement rating, placement, and color on brain activity using near-infrared spectroscopy (NIRS). For that, we used 34 pictorial advertisements, 34 verbal advertisements, and 34 webpages on which the two advertisement types were placed on the right and the left sides of webpage content. First, seven participants viewed the 34 webpages. Subsequently, they viewed the 68 advertisements and rated them on a 7-point scale. Brain activity was measured simultaneously while they viewed the advertisements. The NIRS results indicated that the concentration of oxygenated hemoglobin increased when the participants viewed highly rated advertisements compared with poorly rated ones. In addition, a significant difference in brain activity was also observed in accordance with the placement and color of the pictorial advertisements and the color of verbal advertisements.