WORK VEHICLE, CONTROL DEVICE OF WORK VEHICLE, AND CONTROL METHOD OF WORK VEHICLE

A control device of a work vehicle includes a braking force function determination unit and a required braking force function determination unit. The braking force function determination unit determines at least one of an offset and an inclination for a required braking force in a braking force function which indicates a relationship between a rotational speed of an output shaft of a transmission and the required braking force and in which the required braking force monotonically increases with respect to the rotational speed such that the smaller a stage number of a selected speed stage which is input into a traction force instruction device, the larger an absolute value of at least one of the offset and the inclination. The required braking force function determination unit determines the required braking force based on the rotational speed of the output shaft of the transmission and the braking force function.