Abstract: The invention concerns a device for helping a user fall asleep, comprising a light source designed to emit a substantially monochromatic red or quasi-monochromatic light encouraging the user to fall asleep, characterized in that it comprises a control unit designed to automatically control said light source according to a predefined law according to which the light power emitted by said light source decreases gradually over time in such a way as to change automatically between a maximum power value and a minimum power value, the light power emitted by said light source at a given time always being greater than or equal to the light power emitted at a subsequent time.