A load control device for an engine of a work vehicle that purposes to render the work vehicle, such as a wheel loader or the like, capable of raising a vehicle speed in a short period of time by providing a sufficient traction force when a high traveling load is imposed, without causing degradation of a vehicle body performance, waste of energy, and other problems. The load control device is provided with variable displacement hydraulic pumps (7, 8, 9) being provided with absorption torque changing means (19, 22) for changing absorption torque. A controller (18) determines whether a traveling load is in a high state, and when it has been determined that the traveling load is in the high state, control for lowering the absorption torque for the hydraulic pumps (7, 8, 9) is carried out. This control is carried out, provided, for example, that a "power mode" is selected with the power mode switch (31). The determination that the traveling load is in the high state can be made by determining that the wheel loader (100) is in an acceleration state.