A hybrid work vehicle, comprising: an engine; an electric motor (28, 29); a vehicle body frame; an outer cover; an engine compartment internally housing the engine; a cooling compartment internally housing a cooling device; a partition wall separating the cooling compartment from the engine compartment; an inverter disposed between the partition wall and the cooling device; and a capacitor disposed between the partition wall and the cooling device; wherein: driving force is generated by the engine and by the electric motor (28, 29); characerized in that the cooling device includes a hybrid cooler, which cools cooling water of the inverter and the capacitor; the capacitor is supported upon the vehicle body frame; the inverter is positioned above the capacitor; a length of the inverter in the vehicle width direction is shorter than a length of the capacitor in the vehicle width direction; at least one of a first side surface of the outer cover positioned leftwards from a left side surface of the inverter, and a second side surface of the outer cover positioned rightwards from a right side surface of the inverter is separated from the inverter by a gap; and the inverter is installed as separated from the capacitor in the vertical direction by a gap. an engine; an electric motor (28, 29); a vehicle body frame; an outer cover; an engine compartment internally housing the engine; a cooling compartment internally housing a cooling device; a partition wall separating the cooling compartment from the engine compartment; an inverter disposed between the partition wall and the cooling device; and a capacitor disposed between the partition wall and the cooling device; wherein: driving force is generated by the engine and by the electric motor (28, 29); characerized in that the cooling device includes a hybrid cooler, which cools cooling water of the inverter and the capacitor; the capacitor is supported upon the vehicle body frame; the inverter is positioned above the capacitor; a length of the inverter in the vehicle width direction is shorter than a length of the capacitor in the vehicle width direction; at least one of a first side surface of the outer cover positioned leftwards from a left side surface of the inverter, and a second side surface of the outer cover positioned rightwards from a right side surface of the inverter is separated from the inverter by a gap; and the inverter is installed as separated from the capacitor in the vertical direction by a gap. driving force is generated by the engine and by the electric motor (28, 29); characerized in that the cooling device includes a hybrid cooler, which cools cooling water of the inverter and the capacitor; the capacitor is supported upon the vehicle body frame; the inverter is positioned above the capacitor; a length of the inverter in the vehicle width direction is shorter than a length of the capacitor in the vehicle width direction; at least one of a first side surface of the outer cover positioned leftwards from a left side surface of the inverter, and a second side surface of the outer cover positioned rightwards from a right side surface of the inverter is separated from the inverter by a gap; and the inverter is installed as separated from the capacitor in the vertical direction by a gap.