A method of assembling a fluid dispenser device, the method comprising the following steps: pre-assembling a first unit comprising a body (10) and a lateral actuator system (40), said lateral actuator system including a presser element (42) that is mounted on the body (10) to pivot about an axis (A), an actuator element (41) being mounted on said presser element (42) to pivot about an axis (B), said presser element (42) having a pre-assembled position in which said lateral actuator system (40) is blocked; assembling a second unit, comprising a dispenser member (30), such as a pump or a valve, that is mounted on a reservoir (20) by means of a fastener ring (60), in said first pre-assembled unit; and moving said presser element (42) from its pre-assembled position to a final assembled position that is axially offset from said pre-assembled position, and in which said actuator element (41) co-operates operationally with said fastener ring (60) so as to actuate said dispenser member (30) each time the lateral actuator system is actuated.