A vibration isolator comprising: a first tubular attachment member connected to one of a vibration generating unit and a vibration receiving unit and a second attachment member connected to the other unit; an elastic body configured to elastically connect the first attachment member and the second attachment member; a partition member disposed inside the first attachment member and configured to partition a liquid chamber formed inside the first attachment member into a main liquid chamber using the elastic body as a portion of a wall surface and disposed at one side in an axial direction and a subsidiary liquid chamber disposed at the other side in the axial direction; and a movable plate displaced according to a pressure difference between the main liquid chamber and the subsidiary liquid chamber, wherein an accommodating chamber configured to accommodate the movable plate, a first communication hole configured to bring the accommodating chamber in communication with the main liquid chamber, and a second communication hole configured to bring the accommodating chamber in communication with the subsidiary liquid chamber are formed in the partition member, the main liquid chamber and the subsidiary liquid chamber are in communication with each other through the accommodating chamber, the first communication hole and the second communication hole, and an opening area in the partition member of the first communication hole is larger than that in the partition member of the second communication hole, characterized in that a plurality of ribs are formed at an inner circumferential surface of the first communication hole to protrude inward in the radial direction; a plurality of crosslinking sections configured to connect opposite portions in the radial direction of an inner circumferential surface of the second communication hole are formed to protrude from an inner circumferential surface of the second communication hole; the crosslinking sections are disposed about the central axis of the vibration isolator at a position deviated by 90°; and the size in the circumferential direction of each crosslinking section is larger than the width of each rib. a first tubular attachment member connected to one of a vibration generating unit and a vibration receiving unit and a second attachment member connected to the other unit; an elastic body configured to elastically connect the first attachment member and the second attachment member; a partition member disposed inside the first attachment member and configured to partition a liquid chamber formed inside the first attachment member into a main liquid chamber using the elastic body as a portion of a wall surface and disposed at one side in an axial direction and a subsidiary liquid chamber disposed at the other side in the axial direction; and a movable plate displaced according to a pressure difference between the main liquid chamber and the subsidiary liquid chamber, wherein an accommodating chamber configured to accommodate the movable plate, a first communication hole configured to bring the accommodating chamber in communication with the main liquid chamber, and a second communication hole configured to bring the accommodating chamber in communication with the subsidiary liquid chamber are formed in the partition member, the main liquid chamber and the subsidiary liquid chamber are in communication with each other through the accommodating chamber, the first communication hole and the second communication hole, and an opening area in the partition member of the first communication hole is larger than that in the partition member of the second communication hole, characterized in that a plurality of ribs are formed at an inner circumferential surface of the first communication hole to protrude inward in the radial direction; a plurality of crosslinking sections configured to connect opposite portions in the radial direction of an inner circumferential surface of the second communication hole are formed to protrude from an inner circumferential surface of the second communication hole; the crosslinking sections are disposed about the central axis of the vibration isolator at a position deviated by 90°; and the size in the circumferential direction of each crosslinking section is larger than the width of each rib.