<p>How do we interact with mechanical systems? Users command something, and the systems always accept and react it. In other words, it is a "Leader-follower" relationship. Thinking about a scene where you walk in a park with your friend, on the other hand, there are neither a definite leader nor a follower. They co-adjust the walking direction and the pace by considering each other from implicit body movements. We named the relationship that people co-adjust each other "Side-to-side relationship." In this research, we attempt to construct "Side-to-side relationship" between a human and a robot by utilizing a robot platform "Mako-no-te" that can walk hand in hand with its human partner. We conducted an experiment with three conditions; human leading condition, robot leading condition, and co-adjusting condition. As a result, the robot of the co-adjusting condition was evaluated more favorable, active, and lifelike than one of other conditions.</p>