A posture training machine comprises a vertical support structure (12) for resting the back of the user in erected position, such a vertical support structure (12) being of adjustable height and comprising at least five rest elements (18), of which at least three longitudinally positioned at the user's vertebral column and at least a respective one on each side arranged in transversal direction close to the user' s shoulders, in which each of the rest elements (18) is adjustable in height in relation to the plane of the vertical support structure (12) in an independent manner to identify a correct posture and is equipped at the free end with a contact sensor (19), connected with means for the audio/visual signalling (14) of which and/or how many rest elements (18) are activated.