Actuator of a connecting-rod fracture splitting apparatus includes: a piston rod having one end portion extending through a lid of the cylinder and connected to a wedge; and a free piston slidably mounted on the piston rod and abuttable against the upper surface of the piston. By pressure fluid being supplied to act on the upper surface of the piston, the free piston imparts a preload to a hole of a big end section of the connecting rod. By pressure fluid being supplied to act on a region upward of the free piston, the free piston is driven downward to collide against the upper surface of the piston, so that divided mandrel members are moved apart from each other, via the piston rod and the wedge, to fracture a large end section of the connecting rod.