Abstract: An apparatus is provided for training a person to putt a golf ball more accurately. A pair of guide rails each have a generally vertical guide surface and a ground spike for removably fixing the rail on a putting green, carpet, or the like. A horizontal upward facing flange along the top edge of each guide surface maintains rigidity of each guide surface and includes a series of spaced apart guide marks parallel to the guide surface and visible from above. A flat, rigid connecting rod has an elongated slot extending linearly over the length of the rod, has a arcuate segment at one end, and includes a series of spaced apart alignment marks set at right angles to the slot. The slot slidably accepts an attaching pin of one rail for mounting the rail rotatably and slidably in the slot. As such, the rail may be moved to any position along the slot. A pivot mount rotatably accepts an attachment pin of the other of the guide rails so that the other of the rails may be rotated with respect to the connecting rod.