Traditionally, it has been accepted that consumers exposed to advertising form brand attitudes through brand cognition based on the brand information contained in advertisements. However, since the 1980s, it has been accepted that consumers' attitude toward the advertisement also has a considerable influence on brand attitude formation. This study was conducted to investigate the moderating roles of consumers' product category involvement and advertisement type on consumers' information processing routes. The results of this study showed that the influence of brand cognition on brand attitude formation was greater when the level of involvement was high, while the influence of attitude toward the advertisement was greater when the level of involvement was low. The causal relationship of attitude toward the advertisement → brand cognition → brand attitude → purchase intention was found to be more evident when the level of involvement was high rather than low. Additionally, the influence of brand cognition immediately after advertisement exposure on brand attitude after a certain period was found to be greater when the level of involvement was high rather than low. The hypothesis that brand attitude formation routes differ according to advertisement type was not supported, but it is expected to be clarified by future research.