In this paper, we develop a method to impart the chaotic nature to a mobile robot. The chaotic mobile robot implies a mobile robot with a controller that ensures chaotic motions. Chaotic motion is characterized by the topological transitivity and the sensitive dependence on initial conditions. Due to the topological transitivity, the chaotic mobile robot is guaranteed to scan the whole connected workspace. For scanning motion, the chaotic robot does not require the map of workspace. It only requires to measure the local normal of the workspace boundary when it comes close to it. We design the controller such that the total dynamics of mobile robot is represented by the Arnold equation, which is known to show the chaotic behavior of noncompressive perfect fluid. Experimental results and their analysis illustrate the usefulness of the proposed controller.