A one-way wrench having a catching device with two catches and a catch holder and having differential teeth is provided and characterized in that: the catching device is disposed in a catching chamber laterally disposed beside a driving hole of the one-way wrench; the catching device has two catches, two position-restoring elements, and a catch holder; the catch holder pushes the two catches simultaneously, such that a single stable base structure pushes the two catches simultaneously; and starting ends of tooth portions of the two catches are dentate to different extents, so as to effectuate a small transmission-oriented tooth-changing angle, achieve stable control, as well as cut production and maintenance costs.