A vibration isolating apparatus comprising: a first mounting component which is cylindrical and is connected to one of a vibration generating portion and a vibration receiving portion; a second mounting component which is connected to the other one of the vibration generating portion and the vibration receiving portion; a rubber elastic body which is elastically connected to the first mounting component and the second mounting component and which closes off an aperture end on one side of the first mounting component; a diaphragm which closes off an aperture end on the other side of the first mounting component; and a partitioning component that divides a liquid chamber which is formed between the rubber elastic body and the diaphragm and into which a liquid is injected into a main liquid chamber a portion of whose partition walls is formed by the rubber elastic body and whose internal volume is changed by deformation of the rubber elastic body, and an auxiliary liquid chamber a portion of whose partition walls is formed by the diaphragm, characterized in that the partitioning component is formed entirely from an elastic body, and on the first mounting component there are provided a protruding portion which protrudes inwards in a radial direction, and a first cylindrical portion that is located on the other side of the protruding portion, and a toroidal rigid component which is formed from a rigid body which is more rigid than the elastic body is fitted on an inner side of the first cylindrical portion, and in the rigid component there are provided a second cylindrical portion which is located on the same axis as the first cylindrical portion, and a supporting portion which is located on the inner side of the second cylindrical portion and supports the partitioning component, and any one of the first and second cylindrical portions is located inside the other one of the first and second cylindrical portions, and in the one of the first mounting component and the rigid component that is provided with the other cylindrical portion there are formed respectively an engaging portion which engages with one end portion of the one cylindrical portion, and a caulked portion which is folded inwards in a radial direction and which engages with the other end portion of the one cylindrical portion, and the one cylindrical portion is sandwiched between the engaging portion and the caulked portion, and the partitioning component is sandwiched between the protruding portion and the supporting portion. a first mounting component which is cylindrical and is connected to one of a vibration generating portion and a vibration receiving portion; a second mounting component which is connected to the other one of the vibration generating portion and the vibration receiving portion; a rubber elastic body which is elastically connected to the first mounting component and the second mounting component and which closes off an aperture end on one side of the first mounting component; a diaphragm which closes off an aperture end on the other side of the first mounting component; and a partitioning component that divides a liquid chamber which is formed between the rubber elastic body and the diaphragm and into which a liquid is injected into a main liquid chamber a portion of whose partition walls is formed by the rubber elastic body and whose internal volume is changed by deformation of the rubber elastic body, and an auxiliary liquid chamber a portion of whose partition walls is formed by the diaphragm, characterized in that the partitioning component is formed entirely from an elastic body, and on the first mounting component there are provided a protruding portion which protrudes inwards in a radial direction, and a first cylindrical portion that is located on the other side of the protruding portion, and a toroidal rigid component which is formed from a rigid body which is more rigid than the elastic body is fitted on an inner side of the first cylindrical portion, and in the rigid component there are provided a second cylindrical portion which is located on the same axis as the first cylindrical portion, and a supporting portion which is located on the inner side of the second cylindrical portion and supports the partitioning component, and any one of the first and second cylindrical portions is located inside the other one of the first and second cylindrical portions, and in the one of the first mounting component and the rigid component that is provided with the other cylindrical portion there are formed respectively an engaging portion which engages with one end portion of the one cylindrical portion, and a caulked portion which is folded inwards in a radial direction and which engages with the other end portion of the one cylindrical portion, and the one cylindrical portion is sandwiched between the engaging portion and the caulked portion, and the partitioning component is sandwiched between the protruding portion and the supporting portion.