A vibration isolating device includes an insulator for isolating the transmission of an inputted vibration by an elastic deformation. A principal vibration input portion is provided in a central area of a concave curved wall portion formed in the insulator. A thin wall portion and a thick wall portion are formed by relatively varying a thickness of the insulator around the vibration input portion, wherein the concave curved wall portion of the insulator is formed in a substantially circular shape when viewed in a principal vibration inputted direction. The thick wall portion is formed substantially in the shape of a belt of a predetermined width and extends across the concave curved wall portion in the diametrical direction thereof while passing the vibration input portion. A rigid body covering portion for covering a surface of a metallic member of the vibration input portion is provided in the central area of the thick wall portion. A thickness of the rigid body covering portion is at least 1.7 mm.