The engine speed control system for a work vehicle has a foot accelerator controller for carrying out foot accelerator control based on a pedal sensor, a hand accelerator controller for carrying out hand accelerator control based on a lever sensor, a manually operated input device, storage means for storing a predetermined engine speed, and a constant rotation controller for carrying out constant rotation control in which the engine speed stored in the storage means is used as the target rotational speed on the basis of an input to the input device. The constant rotation control is carried out when the input device has been operated in the case that the engine speed that corresponds to the output of the lever sensor is greater than an idling speed, and the constant rotation control is terminated when the input device is operated in the case that the engine speed that corresponds to the output of the lever sensor is equal to or less than the idling speed.