PURPOSE: To train a swing axis by correcting an angle between the waist and the backbone by providing a means arranged on the back of a player along with the backbone and which supplies stimulus to make the player feel the setting of the backbone as an axis according to the twisting of the body.

CONSTITUTION: This golf swing axis training instrument 10 is provided with a waist belt 14, a contact member 16 arranged so as to be in contact with the back in the direction of backbone, and an angle adjusting means 18 which adjusts the angle between the waist belt 14 and the contact member 16. The contact member 16 is attached to the waist belt 14 so as to permit the flexion and extension of the back as keeping contact with the back when the player 12 flexes and extends the upper half of the body starting from the waist. The angle adjusting means 18 consists of a nut 24 to be screwed with a screw 22 for angle adjustment protruding over the waist belt 14, a U-shape member 26 whose almost center part is inserted to the screw 22 and formed so as to press the surface of the waist belt 14 and that of the contact member 16 by both terminal parts, and an elastic member 28 which permits the turning of the contact member 16 according to the flexion and extension of the body.