To ensure a stable vibration controlling property to a road surface reaction force by a simple constitution for either one of a left-hand drive specification vehicle or a right-hand drive specification vehicle in an electric power steering device for vehicle.

For this electric power steering device 10 for vehicle, the worm wheel 32 of a worm gear type retarder mechanism 30 is fixed to the pinion shaft 21 of a rack and pinion mechanism 20. In a left-hand drive specification vehicle, the direction of the twisting angle β of a helical pinion 21A which is provided on the pinion shaft 21 and the direction of the advancing angle γ of the worm wheel 32 are reversed.