A power steering device includes a bearing rotatably supporting the tip side of a worm shaft, a gear case provided with the housing hole for housing the worm shaft and a holder housing the bearing. The holder includes a first holder holding the bearing, a second holder having the guide part configured to guide a movement of the second bearing toward a worm wheel, and a spring provided in a compressed state between the first holder and the second holder and configured to bias the first holder toward the worm wheel. The second holder includes a holder opening part configured to allow the bearing and the first holder to pass through thereof in the guiding direction of the guide part to guide the bearing, and the first holder faces an inner peripheral surface of the housing hole through the holder opening part.