A power driven marine ladder apparatus includes a vertically extendable cable section and a horizontally extendable rung section connected transversely to the cable section. An axially rotatable winder is mounted on a marine vessel or fixed marine structure and the cable section is attached to and wrappable about the winder. A motor drives the winder rotatably in a first direction to unwrap the cable section and lower the ladder apparatus, and in an opposite second direction to wrap the cable section on the winder and raise the ladder apparatus.