This study was conducted to verify what factors can have positive effects on consumers’ responses, in the context of brand activism advertisement. In particular, this study conducted an experimental study on 181 MZ generations whether the issue fit, concreteness of the action and consistency of the brand activism advertisement act as factors affecting the authenticity perceived by consumers, and moreover, investigated what relations the perceived authenticity has with advertising attitude, brand attitude and purchase intention. The findings show that although the issue fit has no significant relation with the perceived authenticity, consumers more highly perceive it when a specific brand activity was described in the brand activism advertisement, than when it was not; when brand showed an activity consistent with the past one through the brand activism advertisement, than when it did not. On the other hand the perceived authenticity was found to have positive effects on attitude toward advertising, attitude toward brand and purchase intention. This study examined the brand activism which recently attracts attention, but has been rarely studied, in the advertising context, and provides a practical implication for brand communication practitioners in making effective strategy.