A vibration isolator comprising: a first attachment member to be attached to one of a vibration generating unit or a vibration receiving unit; a second attachment member to be attached to another of the vibration generating unit or the vibration receiving unit; an elastic member (14, 30) that is provided at the second attachment member and elastically connects the first attachment member and the second attachment member; convex portions (48, 52), each protruded toward the first attachment member with reference to an outer surface (46, 50) of the elastic member (14, 30) opposed to the first attachment member; and concave portions (46C, 46D, 46E, 50C, 50D, 50E, 104), each of which is recessed at a region of the outer surface (46, 50) positioned on a base end side of a respective convex portion (48, 52), forms an extension portion (48F, 48H, 48J, 52F, 52H, 52J) at a side wall portion of the convex portion (48, 52), and forms an opposed face (48G, 481, 48K, 48Q, 52G, 521, 52K) opposed to the extension portion (48F, 48H, 48J, 52F, 52H, 52J); characterised in that: each concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104) is extended along at least two directions orthogonal to a protrusion direction of the respective convex portion (48, 52) so as to cover a circumference of the convex portion (48, 52), and when input in a twisting direction is applied to each of the convex portions (48, 52), each convex portion (48, 52) is inclined in a direction corresponding to the twisting direction, then a respective wall surface (48C, 48D, 48E, 52C, 52D 52E) on a base end side of the convex portion (48, 52), or the respective extension portion (48F, 48H, 48J, 52F, 52H, 52J) comes into contact with the opposed face (48G, 481, 48K, 48Q, 52G, 521, 52K) formed of the respective concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104). a first attachment member to be attached to one of a vibration generating unit or a vibration receiving unit; a second attachment member to be attached to another of the vibration generating unit or the vibration receiving unit; an elastic member (14, 30) that is provided at the second attachment member and elastically connects the first attachment member and the second attachment member; convex portions (48, 52), each protruded toward the first attachment member with reference to an outer surface (46, 50) of the elastic member (14, 30) opposed to the first attachment member; and concave portions (46C, 46D, 46E, 50C, 50D, 50E, 104), each of which is recessed at a region of the outer surface (46, 50) positioned on a base end side of a respective convex portion (48, 52), forms an extension portion (48F, 48H, 48J, 52F, 52H, 52J) at a side wall portion of the convex portion (48, 52), and forms an opposed face (48G, 481, 48K, 48Q, 52G, 521, 52K) opposed to the extension portion (48F, 48H, 48J, 52F, 52H, 52J); characterised in that: each concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104) is extended along at least two directions orthogonal to a protrusion direction of the respective convex portion (48, 52) so as to cover a circumference of the convex portion (48, 52), and when input in a twisting direction is applied to each of the convex portions (48, 52), each convex portion (48, 52) is inclined in a direction corresponding to the twisting direction, then a respective wall surface (48C, 48D, 48E, 52C, 52D 52E) on a base end side of the convex portion (48, 52), or the respective extension portion (48F, 48H, 48J, 52F, 52H, 52J) comes into contact with the opposed face (48G, 481, 48K, 48Q, 52G, 521, 52K) formed of the respective concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104). each concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104) is extended along at least two directions orthogonal to a protrusion direction of the respective convex portion (48, 52) so as to cover a circumference of the convex portion (48, 52), and when input in a twisting direction is applied to each of the convex portions (48, 52), each convex portion (48, 52) is inclined in a direction corresponding to the twisting direction, then a respective wall surface (48C, 48D, 48E, 52C, 52D 52E) on a base end side of the convex portion (48, 52), or the respective extension portion (48F, 48H, 48J, 52F, 52H, 52J) comes into contact with the opposed face (48G, 481, 48K, 48Q, 52G, 521, 52K) formed of the respective concave portion (46C, 46D, 46E, 50C, 50D, 50E, 104).