A hole cover comprising: a tubular fitting member, to be fitted to a tubular portion of a rack housing which houses a pinion shaft which partially protrudes from the tubular portion, the hole cover, when fitted, covering the pinion shaft and a through hole of a dash panel of a vehicle, the pinion shaft being inserted through the through hole; and an annular seal member disposed radially inward of the tubular fitting member, wherein the tubular fitting member includes: a cover-side fitting portion to be fitted to an outer periphery of a tubular housing-side fitting portion provided on the tubular portion; a cover-side interposing portion configured to interpose the annular seal member in an axial direction between the cover-side interposing portion and a housing-side interposing portion provided on the tubular portion; and a covering portion that covers an outer periphery of the annular seal member, and wherein the covering portion is provided with an opening passing in and out through the covering portion, characterized in that, the opening is provided so that the annular seal member is exposed to an outside in a state in which the fitting of the tubular fitting member to the tubular portion is completed, namely when a fitting length, which is a length of a part of the cover-side fitting portion that is fitted to the tubular housing-side fitting portion, is a predetermined fitting length, and in a state in which the rack housing is not mounted on a vehicle. a tubular fitting member, to be fitted to a tubular portion of a rack housing which houses a pinion shaft which partially protrudes from the tubular portion, the hole cover, when fitted, covering the pinion shaft and a through hole of a dash panel of a vehicle, the pinion shaft being inserted through the through hole; and an annular seal member disposed radially inward of the tubular fitting member, wherein the tubular fitting member includes: a cover-side fitting portion to be fitted to an outer periphery of a tubular housing-side fitting portion provided on the tubular portion; a cover-side interposing portion configured to interpose the annular seal member in an axial direction between the cover-side interposing portion and a housing-side interposing portion provided on the tubular portion; and a covering portion that covers an outer periphery of the annular seal member, and wherein a cover-side fitting portion to be fitted to an outer periphery of a tubular housing-side fitting portion provided on the tubular portion; a cover-side interposing portion configured to interpose the annular seal member in an axial direction between the cover-side interposing portion and a housing-side interposing portion provided on the tubular portion; and a covering portion that covers an outer periphery of the annular seal member, and wherein the covering portion is provided with an opening passing in and out through the covering portion, characterized in that, the opening is provided so that the annular seal member is exposed to an outside in a state in which the fitting of the tubular fitting member to the tubular portion is completed, namely when a fitting length, which is a length of a part of the cover-side fitting portion that is fitted to the tubular housing-side fitting portion, is a predetermined fitting length, and in a state in which the rack housing is not mounted on a vehicle.