In fast-moving and complex App Store, there is a need for exploring the content of mobile application services themselves. Thus, this research empirically analyzes the relationships among mobile application services to identify their structures and positions through a text-mining-based network analysis. Associations among categories and applications are visualized as macro-level category network and micro-level app network; network indexes gauge the structural properties and positional characteristics of each network. Mobile service categories are compared according to their values and grouped according to network properties using cluster analysis, offering implications for the sectoral characteristics of mobile services in App Store.