In this paper, we propose a novel method for a humanoid robot to recover its standing posture from different fallen postures. In the proposed method, the robot estimates its posture using the ground-contacting information, which is sensed by the joint angle information and pressure sensors attached to the whole body. Then, the robot searches a motion sequence based on the estimated posture to stand up. The robot preserves every successful motion sequence into the tree structure to be reused in the next time. To verify the proposed algorithm, we conducted evaluation experiments by employing a real robot. The results show that the proposed method enables the robot to successfully search the motion sequence for standing up from the fallen posture.