This paper proposes a wearable interface for a tendon-driven robotic hand prosthesis. The proposed interface is composed of a dataglove to measure finger and wrist joint angle, and a micro-control board with a wireless RF module. The interface is used for posture control of the robotic hand prosthesis. The measured joint angles by the dataglove are transferred to the main controller via the wireless module. The controller works for directly controlling the joint angle of the hand or for recognizing hand postures using a pattern recognition method such as LDA and k-NN. The recognized hand postures in this study are the paper, the rock, the scissors, the precision grasp, and the tip grasp. In experiments, we show the performances of the wearable interface including the pattern recognition method.