A liquid−in vibration isolating device used to support a vibrating body, such as an automobile engine, in a vibration isolating manner and arranged to prevent a diaphragm from producing a hitting sound or from sticking to a diaphragm when the diaphragm abuts against a partitioning body, without having to increase the volume of an auxiliary chamber on the diaphragm side, and to satisfactorily retain its function. A liquid−in vibration isolating device comprising a cylindrical main body metal fitting (1), a boss metal fitting (2), these fittings being joined through a vibration isolating base (3), a diaphragm (4) provided in an upper end opening, a partitioning body (10) for partition into a main liquid chamber (6) on the vibration isolating base side and an auxiliary liquid chamber (7) on the diaphragm side, an orifice (8) in the outer periphery establishing communication between the two liquid chambers, and a plurality of ridges (17) formed on at least one of the two surfaces, the inner surface of the diaphragm (4) and the plate surface of the partitioning body (10) which are opposed to each other within the auxiliary liquid chamber (7), for example, the surface of the central plate portion of the partitioning plate (10) opposed to the diaphragm (4) such that the abutment of the diaphragm (4) against the partitioning body (10) is controlled to avoid surface contact.
