Ray tracing is a 3D rendering method which simulates the path of light. This technique can represent high quality visual realism, but it requires great computing power. Because of the insufficient computing power in mobile device, some hardware accelerator is required for mobile real-time ray tracing. In this work, we propose a novel hardware unit which has two-AABB (Axis Aligned Bounding Box) traversal architecture. Our architecture has two ray-AABB testing units and the efficient leaf node processing mechanism. The experimental results show that our hardware architecture has half the gate count and is up to 2.9 times faster than the existing single pipeline architecture.