A vibration isolator (10) includes a first attachment member (11), a second attachment member (12), an elastic body (13), and a partition member (16) configured to partition a liquid chamber in the first attachment member in which a liquid (L) is sealed into a first liquid chamber (14) and a second liquid chamber (15). A communicating passage (30) configured to communicate the first liquid chamber with the second liquid chamber is provided in the partition member. A flow changing protrusion (31) is provided at an inner circumferential surface (30a) of the communicating passage. A guide surface (32) opposite to the communicating passage and intersecting the axial direction (O) of the communicating passage is provided at the flow changing protrusion. A passing hole (34) which is open toward both sides in the axial direction is formed by a projecting end (31b) of the flow changing protrusion and another place on the inner circumferential surface (30b) of the communicating passage. The flow changing protrusion changes the flow of the liquid flowing in the communicating passage and reaching the guide surface toward the projecting end. The guide surface is formed in a concave curved surface shape which is recessed in the axial direction.