A tractor vehicle operation control device includes a yaw rate sensor, which detects the actual yaw rate, and a controller, which executes damping control for increasing braking power on the vehicle wheels based on the actual yaw rate and damping periodic yaw motion of the tractor vehicle originating in a trailer. The controller, based on the actual yaw rate, calculates a yaw indicator representing the degree of yaw motion, and sets the front wheels braking power to be greater and sets the rear wheels braking power to be less as the yaw indicator increases. For example, the controller calculates a peak value of the actual yaw rate and determines the actual yaw rate peak value to be the yaw rate. The controller also may calculate yaw angular acceleration based on the actual yaw rate and determine a yaw indicator based on the peak value of the yaw angular acceleration.