Understanding human intention is an essential function for a robot which can offer adequate support to human beings. It requires smooth communication between the human and the robot. Human behavior is an expressive media of communication. This paper proposes a new function of“active understanding of human intentions”by a robot through monitoring of human behavior. The unique feature of the proposed function lies in the fact that it utilizes multi-communication channels in parallel, i.e., human intentions are understood not only through conscious behavior but also through unconscious behavior. The paper also proposes a robot architecture to realize the function. Following points are the key features of the architecture: 1) A robot possesses multi-sensors which surround the human. 2) Information processing is carried out by dual loops — a loop for information exchange between the human and the robot and a loop for human intention understanding. As an example of a robot with the human intention understanding functions, the authors constructed a micro-teleoperation robot. It can automatically understand an operator's intention through such unconscious behavior of touching a desk with an operator's hand which holds a pen-shaped master. The understood result is utilized to change the control mode of a master-slave manipulation system from fine motion to rough motion and vice versa. The experimental results prove that the proposed function is effective in making the operation of the system easier. Consequently the system is friendly to the operator.