A hub unit for an electric power-assisted human powered vehicle comprising, inside a hub case which rotates around an axle of the vehicle: a speed-change mechanism portion transmitting a rotation output of a tread force from a pedal to the hub case so as to be capable of changing a speed of the rotation output; a driving electric motor; and a speed-reduction mechanism portion decelerating a rotation output of the driving electric motor and transmitting the rotation output to the hub case, wherein the speed-change mechanism portion, the speed-reduction mechanism portion and the driving electric motor are aligned in an axial direction of the axle, wherein the speed-change mechanism portion is characterized by: a speed-change sun gear to be connected to the axle, a speed-change output ring gear to be connected to the hub case, a speed-change carrier rotatably supported on the axle and receiving the tread force from the pedal; and a speed-change pinion rotatably supported on the speed-change carrier and meshing with the speed-change sun gear and the speed-change output ring gear, the speed-reduction mechanism portion includes: a speed-reduction sun gear rotatably supported on the axle and receiving a rotation output of the driving electric motor; a stationary speed-reduction ring gear protruding inwardly in a radial direction from a motor case unrotatably fixed to the axle; a speed-reduction output ring gear protruding from the hub case inwardly in the radial direction of the stationary speed-reduction ring gear; a speed-reduction carrier rotatably supported on the axle; and a speed-reduction pinion rotatably supported on the speed-reduction carrier and coaxially including a first gear meshing with the speed-reduction sun gear and the stationary speed-reduction ring gear, and a second gear meshing with the speed-reduction output ring gear, and on a projection plane to a section perpendicular to the axle, pitch circles of the stationary speed-reduction ring gear, the speed-reduction output ring gear and the speed-change output ring gear are arranged inwardly in the radial direction of an outer periphery of a stator of the driving electric motor. a speed-change mechanism portion transmitting a rotation output of a tread force from a pedal to the hub case so as to be capable of changing a speed of the rotation output; a driving electric motor; and a speed-reduction mechanism portion decelerating a rotation output of the driving electric motor and transmitting the rotation output to the hub case, wherein the speed-change mechanism portion, the speed-reduction mechanism portion and the driving electric motor are aligned in an axial direction of the axle, wherein the speed-change mechanism portion is characterized by: a speed-change sun gear to be connected to the axle, a speed-change output ring gear to be connected to the hub case, a speed-change carrier rotatably supported on the axle and receiving the tread force from the pedal; and a speed-change pinion rotatably supported on the speed-change carrier and meshing with the speed-change sun gear and the speed-change output ring gear, a speed-change sun gear to be connected to the axle, a speed-change output ring gear to be connected to the hub case, a speed-change carrier rotatably supported on the axle and receiving the tread force from the pedal; and a speed-change pinion rotatably supported on the speed-change carrier and meshing with the speed-change sun gear and the speed-change output ring gear, the speed-reduction mechanism portion includes: a speed-reduction sun gear rotatably supported on the axle and receiving a rotation output of the driving electric motor; a stationary speed-reduction ring gear protruding inwardly in a radial direction from a motor case unrotatably fixed to the axle; a speed-reduction output ring gear protruding from the hub case inwardly in the radial direction of the stationary speed-reduction ring gear; a speed-reduction carrier rotatably supported on the axle; and a speed-reduction pinion rotatably supported on the speed-reduction carrier and coaxially including a first gear meshing with the speed-reduction sun gear and the stationary speed-reduction ring gear, and a second gear meshing with the speed-reduction output ring gear, and a speed-reduction sun gear rotatably supported on the axle and receiving a rotation output of the driving electric motor; a stationary speed-reduction ring gear protruding inwardly in a radial direction from a motor case unrotatably fixed to the axle; a speed-reduction output ring gear protruding from the hub case inwardly in the radial direction of the stationary speed-reduction ring gear; a speed-reduction carrier rotatably supported on the axle; and a speed-reduction pinion rotatably supported on the speed-reduction carrier and coaxially including a first gear meshing with the speed-reduction sun gear and the stationary speed-reduction ring gear, and a second gear meshing with the speed-reduction output ring gear, and a first gear meshing with the speed-reduction sun gear and the stationary speed-reduction ring gear, and a second gear meshing with the speed-reduction output ring gear, and on a projection plane to a section perpendicular to the axle, pitch circles of the stationary speed-reduction ring gear, the speed-reduction output ring gear and the speed-change output ring gear are arranged inwardly in the radial direction of an outer periphery of a stator of the driving electric motor.