A fluid dispenser device comprising: at least one predosed reservoir (10) that is hermetically sealed and that contains a single dose of powder; an expulsion channel (20) that is terminated by a mouthpiece; and a reservoir opening system (30), each reservoir (10) including a closure layer (12) that is suitable for being pierced and/or torn by said opening system (30) so as to enable the powder that is contained in said reservoir (10) to be expelled through said expulsion channel (20), said reservoir opening system (30) comprising at least two piercer elements (31) that are actuated so as to create at least two distinct openings (25, 26) in said closure layer (12), forming at least one inlet passage (25) for the flow of gas, in particular air, and at least one outlet passage (26) for the powder entrained by said flow of gas, and said device including an inhalation trigger system (50) that creates a flow of gas in said expulsion channel (20) only when a user inhales at or above a predetermined inhalation threshold.