As smart devices have proliferated and mobile networks have accelerated, various wired IT(Information Technology) services are transplanted in wireless environments. Cloud computing service, enabling individual users or firm users to download data from a server and upload data after manipulating data, is also available in mobile devices. Unlike cloud service in wired network environments, mobile cloud service provides differentiated aspects in mobility, security issues caused by persistent connection to networks. In this paper we aim to analyze the factors affecting the user attitude and their structural relationships towards mobile cloud service use. We extend TAM(Technology Acceptance Model) to consider the characteristics of mobile environments. Research findings, analyzed by SEM(Structural Equation Model), are explained and practical implications are presented with concluding remarks.