An electric power steering device, comprising an upper bracket, a steering column, a steering shaft rotatably fitted into the steering column, a tilt mechanism having a tilt clamp tightening the steering column between the tightening plate parts of the upper bracket and a tilt pivot swinging the steering column, an electric assist device installed at the lower end of the steering column, and a lower bracket fixed to a vehicle body on the anti-steering column side of the electric assist device and pivotally supporting the pivot shaft of the tilt pivot. The housing of the electric assist device is loosely engaged with the pivot shaft of the tilt pivot, the steering column is formed swingable about the pivot shaft, and a column rotation restriction part is installed between the lower bracket and the housing.