An in-wheel motor drive device comprising: a motor unit ; a wheel hub bearing unit ; a speed reduction unit that reduces the rotational speed of the motor unit and transmits the reduced rotational speed to the wheel hub bearing unit ; and a carrier that is linked to a vehicle body member, wherein the wheel hub bearing unit includes an outer ring disposed on an axially outer side of the wheel hub bearing and coupled to a wheel (W), a stationary shaft passing through a center bore of the outer ring , and a plurality of rolling elements arranged in an annular space between the outer ring and the stationary shaft , the motor unit and the speed reduction unit are disposed to offset from an axis (O) of the wheel hub bearing unit in a direction perpendicular to the axis (O), the motor unit is disposed adjacent to an axially inner end portion of the stationary shaft , the speed reduction unit includes an output gear coupled to the outer ring , and a rolling bearing provided between the output gear and the stationary shaft to rotatably support the output gear , and the carrier is disposed on an axially inner side relative to the wheel hub bearing unit , and secured to the axially inner end portion of the stationary shaft , wherein the speed reduction unit includes a casing wall part that is disposed on the axially inner side relative to the wheel hub bearing unit , and is coupled to the axially inner end portion of the stationary shaft , characterized in that the stationary shaft includes a projecting portion at the axially inner end portion thereof, the projecting portion projecting radially outward relative to an axially outer end portion of the stationary shaft , and the projecting portion and the motor unit are disposed to overlap each other when viewed in the direction of the axis (O) of the wheel hub bearing unit . a motor unit ; a wheel hub bearing unit ; a speed reduction unit that reduces the rotational speed of the motor unit and transmits the reduced rotational speed to the wheel hub bearing unit ; and a carrier that is linked to a vehicle body member, wherein the wheel hub bearing unit includes an outer ring disposed on an axially outer side of the wheel hub bearing and coupled to a wheel (W), a stationary shaft passing through a center bore of the outer ring , and a plurality of rolling elements arranged in an annular space between the outer ring and the stationary shaft , the motor unit and the speed reduction unit are disposed to offset from an axis (O) of the wheel hub bearing unit in a direction perpendicular to the axis (O), the motor unit is disposed adjacent to an axially inner end portion of the stationary shaft , the speed reduction unit includes an output gear coupled to the outer ring , and a rolling bearing provided between the output gear and the stationary shaft to rotatably support the output gear , and the carrier is disposed on an axially inner side relative to the wheel hub bearing unit , and secured to the axially inner end portion of the stationary shaft , wherein the speed reduction unit includes a casing wall part that is disposed on the axially inner side relative to the wheel hub bearing unit , and is coupled to the axially inner end portion of the stationary shaft , characterized in that the stationary shaft includes a projecting portion at the axially inner end portion thereof, the projecting portion projecting radially outward relative to an axially outer end portion of the stationary shaft , and the projecting portion and the motor unit are disposed to overlap each other when viewed in the direction of the axis (O) of the wheel hub bearing unit . <EOS>