A 360° bi-directional rotary hinge formed of a fixed bracket, a rotary bracket, a limiter plate, a stop plate, a positioning plate, a spring ring and a fastening member for use in a folding electronic device is disclosed. Subject to matching between bottom blocks of the limiter plate and arched sliding grooves of the stop plate, movement of the stop plate is constrained by the fixed bracket, and therefore rotation of the rotary bracket of the 360° bi-directional rotary hinge is limited to a forward and backward 360° angle. Further, the stop plate carries an index block corresponding to a −180° angle indication hole and a 180° angle indication hole on the base member of the folding electronic device for giving an indication when the rotary bracket is rotated to +180° or −180° angle relative to the fixed bracket.