A respiratory humidifier (1) for a ventilation system is provided, the humidifier comprising:a housing (2), which is designed essentially in the shape of an “L” with a horizontal and a vertical part (4, 6) and a projecting portion (10) extending from the free end of the vertical part (6) toward the horizontal part (4), and which comprises a control unit, a user interface (12), and a heating plate (8), wherein the user interface (12) is arranged on the projecting portion (10) and the heating plate (8) is arranged on the horizontal part (4) anda liquid container (3), which is designed essentially in the shape of a “U”, comprising a recess (7) and a bottom plate (24) as well as two connector elements (5), each of which establishes a connection with a breathing tubewherein the heating plate (8) can be heated for heating the liquid in the liquid container (3), and the bottom plate (24) can be brought into contact with the heating plate (8)wherein the liquid container (3) can be slid in such a way onto the housing (2) to establish an operating state so that, when in said operating state, the projecting portion (10) of the housing (2) is positioned above the bottom plate (24) of the liquid container (3).