An apparatus (100) is disclosed for treating a user by means of vibrations, comprising: a vessel (1) for accommodating a liquid for immersing the user, provided with a first rim (4); movement means (20) mechanically coupled to the vessel (1) to cause vibrations of the vessel. The apparatus is characterized in that it further comprises an external casing (2) of the vessel (1), provided with a second rim (10) covering the first rim (4), and a fluid-tight seal (11) interposes between the first rim (4) and the second rim and such to reduce the transmission of vibrations from the vessel (1) to the casing (2).