A growing body of research has been conducted attempting to make AR authoring tools for easy creation of AR applications. Existing AR authoring tools are generally categorized as either programming based authoring methods, or non-programming based authoring methods. The former targets the technical developer with professional knowledge of programming. On the other hand, the non-programming based AR authoring methods provide relatively easy and intuitive direct manipulation through graphical elements. They involves novel tangible user interface (TUI) based immersive AR authoring methods, in which users are able to intuitively and immediately modify virtual content using their own hand movements without any programming. In this thesis, we design a tangible user interface-based 6 DOF (Degree of Freedom) direct manipulation method for an in-situ Augmented Reality (AR) authoring. Specifically, we propose virtual hand metaphor-based volume selection and manipulation method to manipulate near 3D objects with high-dimension control. In addition, to insert interactive movement into static 3D object we suggest control points allocation/reconstruction method and dynamic score-based control point manipulation method. Finally, to support 3D object manipulation at far distance with enhanced usability, we suggest a personalized 6 DOF indirect manipulation method. Our method can be applied to immersive/tangible AR based education, game, design, film/animation, military/medical simulation as a 3D user interface.