Disclosed herein is a reclining device for a vehicle seat, which includes a plate holder, a sector tooth rotatably inserted into the plate holder, a pawl tooth engaged with the sector tooth, an operating cam to move the pawl tooth by rotation thereof to fix the sector tooth, a guide bush press-coupled to the operating cam and having a sealing protrusion to support a cam spring, a hollow operation shaft to rotate the operating cam, and the cam spring to restore the operating cam rotated by the operation shaft. Thus, it is possible to prevent a solution for an electrodeposition from infiltrating into the reclining device, to secure a space in which the cam spring is smoothly operated, and to contribute to a reduction in weight by use of the hollow shaft.