Inhaler counter (20) with a ratchet wheel (230) and pawl (210) mechanism (190) for transforming a linear actuation motion into a rotational motion advancing a display means (60), comprising a back rotation prevention means (280) of friction brake type characterized in that the back rotation prevention means (280) is comprised of a cylindrical element (300) supported by two inclined friction surfaces (310) in V-arrangement, the cylindrical element (300) being coupled to the rotational movement of the ratchet wheel and pawl mechanism (190) and urged against the friction surfaces (310) by a spring member (320).
