With the disappearance of boundaries between online and offline, the O2O (online to offline) business connecting the two domains has emerged. Various services that can be utilized in mobile environment are expanding as the advantages of both online and offline channels are combined. Especially, as a platform- based business that integrates individual transactions is recognized as a business that creates value, the intermediary platform market is rapidly growing in the life-friendly service area. This study focuses on the real estate agent O2O service and examines how information and security related factors of real estate apps affect consumers’ trust toward the app, and how trust perception affects intention to use the app. In addition, whether the level of subjective knowledge regarding real estate moderates the relationship between trust perception and intention to use is examined. The present study showed that three antecedents of information quality, security, and the preference for the third party seal positively affect the perceived trust toward the real estate app, and the perceived trust has a significant effect on the intention to use the app. In the case of the group with high subjective knowledge level, unlike the case of the low group, the positive relationship between the trust perception and the use intention was not significant. For consumers with high level of subjective knowledge, even if the real estate app gives credibility by providing various methods, this did not lead to an increase of the intention to use. The result of moderating effect is different from the positive relationship between subjective knowledge level and purchase intention reported in previous studies. In order to increase the use intention of consumers with high level of subjective knowledge, it is suggested that improvement of system quality and legal constraint are necessary as well as product quality management.