Social Network Service has known as the best communication channel to release the branded contents with low cost and high efficiency. Particularly, Facebook is companies’ the most frequently used tool because it has the greatest number of monthly active users among Social Network Services. This study examines the effective ways for companies to communicate with users via Facebook, known as relationship-focused channel. Specially, we applied Social Penetration Theory to examine the relationship between the brand and fans on Facebook Brand Fan Page. Brand self-disclosure and intimacy were chosen as major independent variables to affect mutual communications such as clicking "Like", writing "Comment" and doing "Tag." As a result, for brands with a high level of intimacy, the more they disclosed themselves on Facebook Brand Fan Page, the more users were likely to click "Like". On the other hand, for brands with a low level of intimacy, the less they disclose themselves on Facebook Brand Fan Page, the more users are likely to click "Like". It showed that the interaction between brand self-disclosure and intimacy significantly affects the number of Like. However, there was no effect on writing "Comment" or doing "Share". This study suggests that the levels of brand self-disclosure and intimacy are very crucial factors for companies that want to develop relationships with users in Facebook.