To provide an aid for correctively training the diaphragm which causes shoulder breathing attributed to the atrophy of the diaphragm functionally declined.

A flat membrane base material 1 for mounting fabric (net) bags made from a fabric (net) adapted to tighten the central part of a human breast is arranged and a fabric (net) material 2 for the fabric (net) bags is applied both on the surface and rear of the base material 1 being divided into two chambers, left and right. A bag 3 filled with iron sand is housed into each of fabric (net) bags comprising the fabric (net) material 2 for the fabric (net) bags and the flat membrane base material 1 for mounting fabric (net) bags. A belt 4 around neck made from the fabric (net) is bound across fitting metals 5 and 5 mounted at two corner points above the flat membrane base material 1 for mounting fabric (net) bags. Straps 6 and 6 for application on the waist made from the fabric (net) are extended separately to the length enough to wind the waist doubled from two lower corner points of flat membrane base material 1 for mounting fabric (net) bags.