ArchiMate is used to describe Business, Application and Technology Architectures models for Enterprise Architecture. Although ArchiMate provides mobile architecture modeling capability, it is not mentioned how to show the security related assuredness of mobile architecture modeled by Archi- Mate. In this paper, a method to create security assurance cases from mobile architecture models in ArchiMate is proposed to argue the mobile security. The method can also create security assurance cases for EA models in ArchiMate.