This oscillation prevention device for an elevator main rope is used for an elevator provided with a main rope having one end affixed to a vertically movable body provided in a hoistway in a vertically movable manner, the main rope also having the other end affixed to a balance weight. This oscillation prevention device for an elevator main rope has an oscillation prevention section provided with an oscillation prevention member, and also has a tension application section for applying tension to the oscillation prevention member. The tension application section is provided at the bottom of the hoistway. The oscillation prevention member of the oscillation prevention section is provided around the main rope, has one end affixed to the top of the hoistway and other end affixed to the tension application section, and is in contact with the vertically movable body at a position between the one end and the other end. The oscillation prevention section is provided between the top of the hoistway and the upper part of the vertically movable body.