To provide a travel device with no rattling of a door wheel due to rolling, to be hardly departed from a rail and stable in travelling.

This travel device has a rail 3 provided with a recessed groove 3a extended over a floor 2 in the longitudinal direction and a door wheel 1 provided with a wheel 5 mounted at the lower edge 7 of a sliding door 6 to rotate and travel on the rail 3. A protruded line 14 to be inserted in the recessed groove 3a is peripherally provided at the center of the outer periphery of the wheel 5 and a descending ground plane 13 is formed outside along both sides of the protruded line 14.