A spinal orthosis includes: a pair of waist mounting members (2) fixed to both side surfaces of the waist； and a chest pressing member (3) installed to each waist mounting member. The chest pressing member includes: an arched arm (4) pivotally supported by pivots provided on both side surfaces of the waist mounting members and capable of swinging； a chest pressing body (4a) provided at an upper end portion of the arm； a pressing force giving portion (5, 6) provided at a middle part of the arm and giving a pressing force for pressing the chest pressing body to a chest.
