To provide an electric power steering unit that reduces transmission of torque ripple generated by a motor to a steering and that can improve steering feeling with a simplified structure.

In this electric power steering unit, an auxiliary torque is supplied by a motor to a steering shaft that rotates by a rotation of a steering. A motor torque is transmitted to a steering shaft via a deceleration mechanism. A vibration absorbing mechanism (a vibration absorbing member 27) is provided at a portion where an output shaft (a shaft 21) of the motor and an input shaft (a worm gear 22) of the deceleration mechanism are connected.