To provide a travel stabilizing device for a hydraulic drive type working vehicle effectively improving linear motion stability or turning performance by appropriately distributing drive force to a front axle and a rear axle.

The hydraulic drive type working vehicle is provided with a variable displacement hydraulic pump driven by an engine, a plurality of variable displacement motors 6 rotating with receiving pressurized oil from the hydraulic pump, and wheels 4L, 4R provided on two or more axles 1-3 is driven and rotated by rotary force of the hydraulic motors. The travel stabilizing device for the hydraulic drive type working vehicle is provided with travel condition detection means 41-45 detecting vehicle traveling conditions, and a control means 46 receiving signal from the detection means, and controlling and changing displacement of at least a specific hydraulic motor of the plurality of the hydraulic motors according to the vehicle travel conditions.