Underactuated hands usually have high adaptability in power grasping but they are limited in pinching task with fingertip. In this paper, we propose the design of a tendon-driven underactuated hand that is capable of fingertip pinching by utilizing our proposed coupling mechanism. To reduce the friction resulting from tendon routing, we introduce the carpal tunnel mechanism that replace all sliding-contact tendon routing with the pulley system allocated in 3-dimensional space. The prototype of 11-DOF anthropomorphic robot hand is fabricated using rapid prototyping. Experiments are done to prove the effectiveness of our proposed coupling mechanism and low-friction tendon-driven system for underactuated robot hand.