To provide a protection cover for city-water gauge valve inside a concrete box that a load on a road, an influx of a rainwater and earth or sand do not cause any effect to the gauge valve even if e gauge valve or a city-water duct is buried shallowly into the earth.

The cover is equipped with a first cylinder 10 with a flange part 13 attached in its lower edge which is inserted into a concrete box 50 and a second cylinder 20 which is inserted into it and slides each other with an inner protruding part 23 with a drain hole 231 which protrudes into the cylinder attached in the lower edge. In the upper part of an outer circumferential face 21 of the second cylinder 20, a first rubber hat 30 is attached thereto which adheres to the inner circumferential face of the concrete box 50. Then, the inner protruded part 23 of the second cylinder is put onto a flange 611 of a city-water gauge valve 60. At the same time, the second rubber hat 40 that is inserted from the inner protruded part 23 into a flange cover 61 of the city-water gauge valve 60 is built.