Lunar rovers are required to move on rough terrains such as in craters and rear cliffs where it is scientifically very impor-Tant to explore. Recently, wheel typed rovers are popular for planetary exploration missions. However, there is a problem that the wheel typed rovers have possibility of stack. Therefore, this paper investigates a mechanism of kinetic behavior between the wheels of the exploration rovers and soil. This paper proposed an flexible wheel to solve like that problems. The flexible wheel has the surface which can be changed flexibly toward rough terrain. Running experiments on loose soil which imitated regolith are carried out to observe the traversability of the flexible wheel using slip ratio and sinkage. Traversality of flexible wheel was better than the circular wheel. We believe that stress distribution is important. Therefore, we construct system to measure stress and get information of stress distribution of proposed flexible wheel.