Abstract: A rope braking device includes a base, a one-way pulley, a handle, and a clamping part. The base has a guiding slot extends along a curve path. The one-way pulley is disposed on the base and is rotatable in a direction about a rotation center. A distance that is defined from the rotation center to the curve path is variable and has a relative minimum corresponding to a position of the curve path. The handle is pivotally connected to the base and has another guiding slot. The clamping part is slidably disposed in the two guiding slots simultaneously and opposite to the one-way pulley. When the handle pivots to move the clamping part to the position, a rope wound around the one-way pulley is compressed by the one-way pulley and the clamping part, so that the rope is movable in the direction and is unmovable in the reverse direction.