A robot should know when and how it can move safely without any collision with humans in a space where many people move in various directions. In this paper, we suggest an idea that a robot can move adequately in a complex environment with human crowd. For this purpose, we define the degree of crowd density by using the ratio of blocked space to total space. Current time is also saved to decide more proper motion of a robot with time information. Then, a global path of a robot will be generated under consideration of the elimination of a sudden evasion or a dull motion due to human crowd. Using this idea, a robot will be able to complete its motion without any threat to some vulnerable people such as elders and/or patients.