A fluid spray device having a body (10) provided with a spray orifice (15), a reservoir (20) containing the fluid to be sprayed, a spray device (30) that sprays one or more doses of the fluid contained in the reservoir (20); and an actuator (40) that actuates the spray device (30). The reservoir (20) is closed in a sealed manner before the spray device is actuated for the first time, the body (10) including reservoir opening device (11) adapted to open the reservoir (20) while the device is being actuated. The reservoir (20) forms a sealed unit that is separate from the body (10), filled with fluid and hermetically sealed before it is assembled in the body (10). The body (10) includes a receiver device (13) that receives the reservoir, and a lateral access device that enables the filled reservoir (20) to be assembled sideways into the body (10) and to be secured therein.