IN-WHEEL MOTOR UNIT FOR VEHICLES

An in-wheel motor unit for a vehicle, in which a drive output shaft 10 of a drive unit body A and a wheel hub shaft 70 supported by a hub bearing 71 with respect to an axle case 72 as case member of the drive unit body A are connected via a displacement absorption mechanism B. The displacement absorption mechanism B comprises an output shaft side drive transmission fitting portion 58 which allows to mesh a first inner tooth portion 56 of the drive output shaft 10 and a first outer tooth portion 52 of a gear coupling shaft 50, and a hub shaft side drive transmission fitting portion 59 which allows to mesh a second inner tooth portion 57 of the wheel hub shaft 70 with a second outer tooth portion 54 of the gear coupling shaft 50, wherein the second outer tooth portion 54 of the gear coupling shaft 50 of the displacement absorption mechanism B is arranged axially in the vehicle exterior side with respect to a wheel mounting surface 70g on which a tire wheel 110 is mounted to the wheel hub.