Abstract: An electric power steering apparatus includes a steering torque sensor assembled integrally with a steering device having a variable steering ratio. The steering device includes an input shaft eccentrically and rotatably mounted in a movable housing rotatably supported on a fixed housing, an output shaft rotatably mounted in the fixed housing in eccentric relation to the input shaft, a coupling relatively non-rotatably interconnecting the input and output shafts while allowing them to move relatively to one another in a perpendicular direction of axes of the input and output shafts, and a drive mechanism for rotating the movable housing relatively to the fixed housing to displace the input shaft relatively to an axis of the movable housing so that the eccentricity between the input and output shafts changes to vary the steering ratio of the steering device.