Widely used by national defense sectors, Facebook is a significant new media platform for communicating policies with publics and gaining supports from them. To better understand media agenda setting and priming effects derived from the Facebook’s fan page of spokesman of Ministry of National Defense (SMND), a 3 × 2 between-subjects experiment design was conducted. This study also investigated the relationship between audience’s habits of media use and agenda setting effects. The results showed that the heavier social media dependency that the audience exerts, the more salient agenda setting effect exhibits on exposure of SMND’s Facebook fan page. Implications are also subsequently discussed.