A sternum supporting harness includes a carrying strap structure and a chest strap structure surroundingly disposed thereon. The carrying strap structure includes a main body, a shoulder portion, including a left shoulder strap and a right shoulder strap, a flank portion, and an adjustment portion. One end of the left shoulder strap and one end of the right shoulder strap are connected to two upper end portions of the main body respectively. Another end of the left shoulder strap and another end of the right shoulder strap are both connected to the flank portion. The adjustment portion is connected to the flank portion. The chest strap structure includes a grabbing unit and a belt-like unit connected thereto. The grabbing unit includes a first grabbing portion, a second grabbing portion, and a base portion.