This paper presents the interactive behavior modeling method based on POMDP (Partially Observable Markov Decision Process) for HRI (Human-Robot Interaction). HRI seems similar to conversational interaction in point of interaction between human and a robot. The POMDP has been popularly used in conversational interaction system. The POMDP can efficiently handle uncertainty of observable variables in conversational interaction system. In this paper, the input variables of the proposed conversational HRI system in POMDP are the input information of sensors and the log of used service. The output variables of system are the name of robot behaviors. The robot behavior presents the motion occurred from LED, LCD, Motor, sound. The suggested conversational POMDP-based HRI system was applied to an emotional robot KIBOT. In the result of human-KIBOT interaction, this system shows the flexible robot behavior in real world.