The present invention relates to a protection cap for underground water, including a pipe main body; a cover opening and closing an opening of the pipe main body; and an opening and closing device enabling the cover to rotate only when lifted from the pipe main body. The opening and closing device includes a support member provided on the inner circumference of the pipe main body; a guide member which is inserted into the support member to be able to slide and guides the cover to be lifted upwards; and a rotation member that has one end hinged to the guide member and the other end fixed to the inner surface of the cover and rotates the lifted cover to the outer side of the pipe main body.
