Keeping a living and working spaces tidy is very important for healthy daily life. The efficiency in working rises when the office is tidy. We developed a system that tidies up through the cooperation between a robot and a human. In this study, we investigated the influence of a robot’s behavior on the motivation of tidying up. For completing this system, it is necessary to investigate the effective behaviors that encourages a human. To validate what behavior effectively encourage human to tidy up, we conducted a preliminary experiment with 13 male and 5 female participants, aged 20-23. We found the statistically significant difference between the cases where the robot took actions or not.