Abstract: A device for sanitary treating a sleeping mattress and more particularly a spring mattress and including an internal free volume (18) delimited by upper (12) and lower (14) faces and by a peripheral lateral strip (16). The springs (20) are disposed in the free volume. Ventilation structure is fitted with lateral strips. An injection device (24) injects a treatment gas (25) in the form of a powder or gas contained in a receptacle (26) with a propulsion device (28) of a treatment agent and an injection head (30).