The present invention provides a waterproof structure for a terminal of a wire with a terminal fitting provided with a waterproof block made of resin, the waterproof block covering an end portion of an insulation coated wire which is coupled to a terminal fitting. The waterproof block includes a waterproof portion covering a coupling portion coupling the end portion of the wire and the terminal fitting, the waterproof portion adhering to an outer circumferential surface of an end of an outer skin of the wire, and a cylindrical portion projecting cylindrically from the waterproof portion along the outer skin of the wire. The cylindrical portion has a smaller cross sectional area than the waterproof portion and has rigidity more similar to the outer skin than the waterproof portion in desired bending and torsional directions of the wire and is adhered to an end-adjacent outer circumferential surface of the outer skin.