In pervasive computing environments, where various types of information are publicly owned, and multiple users access the networks via various networked devices anytime and anywhere, access control that grants permission to an authorized user is definitely needed for secure information access. Context awareness refers to the idea that computers can both sense and react based on various context in their environments. In many access control schemes, recently, context awareness has been utilized to guarantee dynamic access control according to current context and various access control schemes utilizing context awareness have been proposed. However, previous studies have difficulty describing conditions for assigning roles and modifying permissions. They also simply consider assigning roles or modifying permissions, rather than providing detailed access control algorithms such as role delegation or role revocation. In this paper, we propose an adaptive access control scheme utilizing context awareness in pervasive computing environments. We design an adaptive access control model based on traditional RBAC(Role-Based Access Control) model, and present an adaptive access control scheme to guarantee dynamic user and permission assignment according to changes of context. In this scheme, we define context requirements in each table, enabling a more detailed description. We also guarantee dynamic access control via various access control algorithms.