Inhaler counter (20) comprising a counter housing (390), a rocker arm (200) with a pawl (210), the rocker arm being pivotally supported by the housing and arranged to perform a rocker movement in response to a linear actuation motion, a return spring (220) for resetting the rocker arm, a ratchet wheel (230) engagable with the pawl to convert the movement of the rocker arm into an incremental rotational motion of an axle arrangement (240) advancing a display means (60), the axle arrangement further comprising a back rotation prevention means (280) in the form of a spring loaded friction brake and a worm gear, the display means comprising rotatable indicator means (120) with teeth that engage the worm-gear and a stationary scale.