To provide a fitting unit capable of reducing operation force required for an operation and reducing cost, and excellent in travelling property by permitting a unit main body to automatically travel when one side of wheels are grounded.

A carrier 9 is rocked with a center shaft 7 as a center till the wheels 8 are grounded and the center shaft 7 is slipped as against a frictive clutch 10 after grounding. The rocking of the carrier 9 is stopped after the wheels 8 are grounded on a ground surface and most of the torques of a driving motor 6 become driving power for rotating the wheels 8 so that a stretcher main body starts to move. While the stretcher main body is moved, the sum of the force of the torques by the rotation of the wheels 8 and the force of weight added to the ground surface is added on the ground surface in an underground direction so that driving force required for travelling is transmitted to the ground surface B without newly adding external force in the ground direction of the wheels 8.