A magnetic roller for being rotatable on a ferromagnetic surface is provided. The magnetic roller includes a roller wheel having an inner space, a magnetic array arrangement and at least one first drive mechanism. Further, the magnetic array arrangement is adapted to be swivelably disposed within the inner space of the roller wheel. The magnetic array arrangement includes a strong adhesion force side and a weak adhesion force side. Furthermore, the first drive mechanism is configured to swivelably drive the magnetic array arrangement. The first drive mechanism swivelably drive the magnetic array arrangement to direct the strong adhesion force side towards the oncoming ferromagnetic surface, and, to direct the weak adhesion force side towards the foregoing ferromagnetic surface to enable the roller wheel to move forward on the ferromagnetic surface.