A device for treating the skin, for instance for removing body hair. The device includes a working head, which includes an irradiating device for irradiating the skin surface to be treated, preferably by means of light; a contact surface surrounding the irradiating device for supporting the working head on the skin surface; and a safety device for controlling the irradiation and/or for providing a safety signal. The safety device includes a recording device for recording the support of the working head on the skin surface. The contact surface defines a bell-like pressure and/or sound chamber and the recording device encompasses an impermeability sensor device for determining the over-pressure and/or sound impermeability of the pressure and/or sound chamber.