Provided is a traveling unit driving apparatus where a driving belt of the traveling unit is manufactured with ease, and concurrently therewith, can be coupled reliably to the unit in a state with high durability.A driving belt extended between a pair of pulleys is formed using a belt with ends and teeth, and a belt fixing means is comprised of a first and second engagement portions provided in the traveling unit, a concave recess portion disposed between the portions, and a lock fixing member that is fitted into the concave recess portion. Then, the first and second engagement portions and the concave recess portion are provided with a first and second mount surfaces for bending and supporting the belt opposite end portions, the lock fixing member is fitted into the concave recess portion, and the belt opposite end portions are thereby sandwiched and held in a bent state. Concurrently therewith, the first and second engagement portions and the lock fixing member are respectively provided with protrusions for engaging in the belt tooth surface.