This paper addresses the zutonomous-decentralized cooperation converyance algorithm to improve the task efficiency by selecting a leader from other robots autonomously. This algorithm aims at coexistence of two exclusive features. One is the effectiveness that is a typical advantage of centralized control systems. The other is the adaptability and robustness to the environment which are advantages of autonomous-decentralized systems. From the several experimental results, the algorithm can improve the task efficiency in the cooperative conveyance task even including human operated agent. Finally, judgement indexes with interaction in order to select the leader is discussed.