PURPOSE: To absorb displacement in a position when slight displacement in a position occurs to the support part of a rack shaft by providing a rocking fulcrum part formed with recessed part and a protrusion between a cylinder holder engaged with the end part of the cylinder hole of a power steering device and the inner wall partition part of the cylinder thereof.

CONSTITUTION: In a power steering device 1, a large piston formed in the middle of a rack shaft 5 moved in the direction of the width of a car through a pinion by rotation of a steering shaft 2 is engaged internally of a cylinder hole 7 of a steering body 3, and cylindrical holders 12 are engaged with the two ends of the cylinder hole 7. In this case, the engaging part between a pinion and a rack 5a is formed in the middle of a cylinder chamber 10 between the one cylinder holder 12 and the large piston. A rocking fulcrum part 23 being a curved contact part formed with a protrusion part 22 in the shape of a curved surface to allow radial rocking operation of the holder 12 and a recessed part 21 engaged with the protrusions formed between the cylinder holder 12 and the inner wall part of the cylinder hole 7 of a body cylindrical part 3b to hold the holder.