The invention relates to a treatment device for stretching the carpal tunnel of the human hand, characterized by at least two adhesive elements, which are suitable to come into contact with human skin and to be applied to the ball of the thumb of a human hand to be treated, and characterized by a stretching device, which is designed to act on the adhesive elements and/or to be connected to the latter and to exert a substantially laterally directed stretching force on the adhesive elements.