An orthosis presenting the shape of a belt and including: - a first strip including a connecting portion provided with at least a posture correcting means, fixing means and an abdominal portion having closing means; - a second strip including a connecting portion provided with at least a posture correcting means, fixing means and an abdominal portion having complementary closing means adapted to cooperate in adjustable manner with the closing means; and - a back panel including o complementary fixing means arranged to cooperate in adjustable manner with the fixing means of the first and second strips (3,4), and ∘ two posture correcting means intended to be positioned on either side of the vertebral column of a patient; the fixing means of the first and second strips (3,4) and the complementary fixing means being shaped in such a way as to authorize a positioning of the posture correcting means of the first strip and the second strip on either side of the posture correcting means of the back panel, the orthosis being characterized in that the first strip comprises a tab comprising first gripping means and being able to be superimposed at least in part to the connecting portion of the second strip comprising first complementary gripping means, the first complementary gripping means being able to cooperate in adjustable manner with the first gripping means, and in that the second strip comprises a tab comprising second complementary gripping means and being able to be superimposed at least in part to the connecting portion of the first strip comprising second gripping means, the second complementary gripping means being able to cooperate in adjustable manner with the second gripping means. - a first strip including a connecting portion provided with at least a posture correcting means, fixing means and an abdominal portion having closing means; - a second strip including a connecting portion provided with at least a posture correcting means, fixing means and an abdominal portion having complementary closing means adapted to cooperate in adjustable manner with the closing means; and - a back panel including o complementary fixing means arranged to cooperate in adjustable manner with the fixing means of the first and second strips (3,4), and ∘ two posture correcting means intended to be positioned on either side of the vertebral column of a patient; the fixing means of the first and second strips (3,4) and the complementary fixing means being shaped in such a way as to authorize a positioning of the posture correcting means of the first strip and the second strip on either side of the posture correcting means of the back panel, the orthosis being characterized in that the first strip comprises a tab comprising first gripping means and being able to be superimposed at least in part to the connecting portion of the second strip comprising first complementary gripping means, the first complementary gripping means being able to cooperate in adjustable manner with the first gripping means, and in that the second strip comprises a tab comprising second complementary gripping means and being able to be superimposed at least in part to the connecting portion of the first strip comprising second gripping means, the second complementary gripping means being able to cooperate in adjustable manner with the second gripping means. o complementary fixing means arranged to cooperate in adjustable manner with the fixing means of the first and second strips (3,4), and ∘ two posture correcting means intended to be positioned on either side of the vertebral column of a patient; the fixing means of the first and second strips (3,4) and the complementary fixing means being shaped in such a way as to authorize a positioning of the posture correcting means of the first strip and the second strip on either side of the posture correcting means of the back panel, the orthosis being characterized in that the first strip comprises a tab comprising first gripping means and being able to be superimposed at least in part to the connecting portion of the second strip comprising first complementary gripping means, the first complementary gripping means being able to cooperate in adjustable manner with the first gripping means, and in that the second strip comprises a tab comprising second complementary gripping means and being able to be superimposed at least in part to the connecting portion of the first strip comprising second gripping means, the second complementary gripping means being able to cooperate in adjustable manner with the second gripping means.