Sliding door support structure

A sliding door support structure slidably supporting a door that can open and close a door opening of a vehicle body, the sliding door support structure comprising:

• a first slide support mechanism including a first slide rail either above the door opening or below the door opening in a vehicle body and regulating an opening and closing path of the door while supporting the door with respect to a vehicle body through the first slide rail;
• and
• a second slide support mechanism including a second slide rail and a third slide rail that are provided below an upper end of the door opening and above a lower end of the door opening in a vehicle body and regulating an opening and closing path of the door while supporting the door, wherein
• the second slide rail and the third slide rail are disposed apart from each other in a vertical direction, and
• the second slide support mechanism regulates an opening and closing path of the door while receiving a weight of the door through the second slide rail and receives force acting in a tilting direction of the door through the second slide rail and the third slide rail.