This study proposes a unique flexible robot with new hydrostatic skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with hydrostatic skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: (i) the robot can change its shape adapting to terrain, (ii) all ground contact areas of the robot are driven toward the same direction. Performance of the first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot demonstrated a capability to pass through a space of 300 [mm] height, whereas the ordinary height of the robot is 420 [mm] .