Torque reduction of an internal combustion engine in case of low level of urea in a work vehicle with selective catalyst reduction

A work vehicle includes: a hydraulic pump (11) driven by an engine (190); a rotational speed detection unit (13) that detects an actual rotational speed of the engine; an exhaust gas purification device (161) that purifies nitrogen oxide in exhaust gas discharged from the engine (190) using a reducing agent solution (urea) stored in a reducing agent tank (162); a remaining amount detection device (163) that detects a remaining amount of the reducing agent solution in the reducing agent tank (162); a torque control unit that decreases output torque of the engine (190) according to decrease of the detected remaining amount of the reducing agent solution; wherein when the actual rotational speed of the engine (190) is not more than a threshold value, the torque control unit does not decrease the output torque of the engine regardless of the detected remaining amount of the reducing agent solution.