Device for disinfecting a liquid by ultraviolet radiation comprising: - a length of cylindrical pipe configured for liquid to flow therein, - at least one source of primary ultraviolet radiation disposed at the outer periphery of the length of cylindrical pipe, the source of primary ultraviolet radiation comprising a lamp which comprises two coaxial cylinders (51, 52), of which one is an outer cylinder and one an inner cylinder forming the length of cylindrical pipe, which are of a dielectric material suitable for transmitting ultraviolet rays and which are connected by their ends so as to define between them a sealed chamber containing a gas, the lamp further comprising a first electrode and a second electrode, the first and the second electrode being connected to a source of alternating current, the lamp being configured to generate ultraviolet radiation between the two coaxial cylinders (51,52), the length of cylindrical pipe and the at least one source of ultraviolet radiation being configured such that the at least one source of ultraviolet radiation irradiates the length of cylindrical pipe and the liquid flowing in the length of cylindrical pipe, from outside the length of cylindrical pipe, and - at least one tube, formed from dielectric material suitable for transmitting ultraviolet rays, which extends the length of cylindrical pipe in extending from at least one outlet of the length of cylindrical pipe to at least one dispensing point of the device, the tube being configured to guide the ultraviolet radiation coming from the length of cylindrical pipe to the at least one dispensing point and irradiate the liquid flowing therein. - a length of cylindrical pipe configured for liquid to flow therein, - at least one source of primary ultraviolet radiation disposed at the outer periphery of the length of cylindrical pipe, the source of primary ultraviolet radiation comprising a lamp which comprises two coaxial cylinders (51, 52), of which one is an outer cylinder and one an inner cylinder forming the length of cylindrical pipe, which are of a dielectric material suitable for transmitting ultraviolet rays and which are connected by their ends so as to define between them a sealed chamber containing a gas, the lamp further comprising a first electrode and a second electrode, the first and the second electrode being connected to a source of alternating current, the lamp being configured to generate ultraviolet radiation between the two coaxial cylinders (51,52), the length of cylindrical pipe and the at least one source of ultraviolet radiation being configured such that the at least one source of ultraviolet radiation irradiates the length of cylindrical pipe and the liquid flowing in the length of cylindrical pipe, from outside the length of cylindrical pipe, and - at least one tube, formed from dielectric material suitable for transmitting ultraviolet rays, which extends the length of cylindrical pipe in extending from at least one outlet of the length of cylindrical pipe to at least one dispensing point of the device, the tube being configured to guide the ultraviolet radiation coming from the length of cylindrical pipe to the at least one dispensing point and irradiate the liquid flowing therein.