A hydraulic damping device including a main damping body protected by a cylindrical portion with downwardly extending side walls. The damping device includes a flexible membrane which has a step portion, a main liquid chamber, an auxiliary liquid chamber and a partition formed in a cup-shape. A passage is made between the step portion of the flexible membrane and the interior of the partition. The partition divides the liquid chamber into a main liquid chamber and an auxiliary liquid chamber. The partition also includes a hole formed therein, a channel and a concave recess formed on the partition side wall between the hole and the channel. This structure permits the main liquid chamber to be connected to the auxiliary liquid chamber through the hole, the passage and the channel. The membrane is inserted into the interior of a cylindrical portion of the main damping body together with the partition and the damping liquid to define a simply constructed sub-assembly. This sub-assembly is subsequently easily inserted into the interior of a cylindrical portion of the supporting member by pressurized insertion.