Based on Davis's Technology Acceptance Model (TAM), this paper aimed to identify the external factors influencing the adoption of wireless Internet and to examine how these external factors affect wireless Internet usage. The research model consisted of external variables (system quality, diversity of service offerings, cost adequacy), mediating variables (perceived usefulness, perceived ease of use), and a dependent variable (wireless Internet usage). A survey was administered to consumers with actual experience using wireless Internet, and the proposed research model was tested through confirmatory factor analysis and path analysis using the survey data. The research results revealed that all external variables (system quality, diversity of service offerings, cost adequacy) affect users' perceived usefulness, and that they influence wireless Internet usage through perceived usefulness. Among the external variables, diversity of service offerings, along with cost adequacy, was identified as the factor with the greatest influence on perceived usefulness. Wireless Internet service providers should offer diverse services so that users perceive them as more useful. Furthermore, the findings suggest that rather than providing cost-intensive services such as VOD, providers should develop and offer services that can reduce the costs borne by users. Since system quality affects the perception of usefulness, which in turn influences usage, continued efforts should be made to ensure that systems are stable and that connection speeds remain satisfactory.