Integrated appstore apparatus, application providing method in said apparatus and integrated appstore system

An integrated app store apparatus of the present invention comprises an authentication server registering and authenticating a client terminal; a content managing server for any one of registering, searching, and downloading an application; a web application server providing a web front for a user; and an interworking server providing an open application programming interface (API) allowing an external app store to access. Thus, by defining a function of an app store in the form of a standard-based common interface (open API) and supporting various terminals and platform environments, an open app store model available for effectively expanding services no matter whether a type of a user terminal, a service type, or a business environment is changed is provided.