A mobile robot apparatus is disclosed. The mobile robot apparatus comprises: a main body; a first wheel and a second wheel provided on opposite sides of the main body, respectively; a first driving device configured to rotate the first wheel and the second wheel; a second driving device configured to rectilinearly move the main body along a reference axis inclined at a predetermined angle so as to be more forward than the vertical line; and a processor for controlling the second driving device so that the main body moves in the traveling direction of the mobile robot apparatus if the mobile robot apparatus accelerates, and the main body moves in the opposite direction of the traveling direction if the mobile robot apparatus decelerates.