To provide an electric power steering device capable of securing straightl advancing stability of a vehicle, without firmly keeping steering of a steering wheel, even in a car body inclined state of the vehicle of traveling straightly.

When a state of being smaller in a pinion angle T2 of a pinion shaft 23 than a predetermined angle threshold value 0 (5) and being larger in steering shaft torque T transmitted to a steering shaft 22 than a predetermined torque threshold value T0 (0.3 Nm), continues for 1 sec or more in the same rotational direction, assist force is generated in a motor 40 for reducing the steering shaft torque T of this steering shaft 22 to become 0 (zero).