Fluid or powdery product dispensing device

A dispenser device for dispensing a fluid or powder composition, the dispenser device including a dispenser head provided with a dispenser opening, an air expeller for generating a flow of air while the device is being actuated, and at least one reservoir that contains a single dose of composition, said at least one reservoir including an air inlet that is connected to said air expeller, and a composition outlet that is connected to said dispenser opening, said at least one reservoir being mounted in removable manner on said air expeller such that, after the device has been actuated, the empty reservoir can be removed from said air expeller and replaced with a new full reservoir, said air expeller being adapted to return to its rest position so as to make a new actuation possible with said new full reservoir, said air inlet being closed by a first closure element and said composition outlet being closed by a second closure element, said device including a mechanical opening system that co-operates with said first and second closure elements so as to expel each closure element mechanically from its respective closed position while the device is being actuated, the device being characterized in that said mechanical opening system comprises a first rod that is secured to said air expeller, and a second rod that is secured to said dispenser head, each of said first and second rods co-operating with a respective closure element during actuation, so as to expel it mechanically from its closed position.