To realize swing operation and rotating operation by a simple structure and different operations by the slight replacement of parts in a steering device for a vehicle in which four wheels 61, 62, 71, and 72 for traveling are disposed at the right side front and rear and the left side front and rear of a deck 1.

In this steering device, a left side shaft 2 and a right side shaft 3 extending in the longitudinal direction are disposed on the deck 1, and both shafts 2 and 3 are rotatingly driven by a left side steering motor 20 and a right side steering motor 30. Worms 21 and 22 are fixed to both ends of the left side shaft 2, and worms 31 and 32 are fixed to both ends of the right side shaft 3. The four worms 21, 22, 31, and 32 and four worm wheels 41, 42, 51, and 52 meshed with these worms are disposed on the deck 1. The wheels are driven by the rotation of the worm wheels in the steering direction.