To solve the problem that though slow turn which has a drive rotation difference in the right and left crawlers and steering turns or brake turn which cuts off one side drive or turns with braking are performed in a crawler traveling vehicle, there are a lot of cases of a state at high speed rotation in a clutch gear or the like where these side clutch operations are performed and smooth engagement or disengagement is hardly performed in the side clutch in an engagement mode.

The working vehicle is provided with a center gear 2 at the central part on a clutch shaft 1, and a side clutch gear 3 which can be engaged by moving in the axial direction on both right and left side parts of the center gear 2. The constitution of the traveling transmission device is characterized in that a low speed gear 4 having a lower rotation ratio than the center gear 2, a brake clutch 5 engaged with the low speed gear 4, and a side brake 6 being braked by pressing at the time of the brake clutch off are mounted at the shaft.