A taphole structure of a melting furnace includes: a sleeve made of a fire-resistant brick, which is disposed inside a tapping hole provided in a furnace wall brick; and a ramming material which fills a gap between the sleeve and the tapping hole for fixing the sleeve. In addition, a repair method of the taphole which has expanded due to wear of a first ramming material during tapping, includes: forming a dismantled surface having a straight line shape by dismantling and removing a worn portion of the first ramming material in a straight line from an outer surface side toward an inner surface side of a furnace wall; and then filling a second ramming material into a gap between the dismantled surface having the straight line shape and a first sleeve for sealing.