A folding device is configured at the pivot between the rear leg frame and the front leg frame of a high chair and allows a user to complete folding process by pressing a driving member. When the driving member is pressed, an engaging member of the folding device moves correspondingly to an unlocked position, so that the rear leg frame disengages from and pivots about the front leg frame. The high chair can then be folded easily for the user, and the structure of the invention is simpler than the prior art.