PURPOSE: To prevent a rubbing failure between a manhole and a road surface by isolating preliminarily a movable portion of a receiving frame for its height adjustment from a pavement or a base in adjusting the height of the manhole cover.

CONSTITUTION: A parting board comprises a combination of a basic ring 1 and an auxiliary ring 2 where the basic ring 1 is as high as a receiving frame 5 and the auxiliary ring 2 is provided just to adjust the height. Then, the receiving frame 5 and a manhole lid 4 are instal led where the rings 1 and 2 are installed around the periphery area in such a fashion that the upper end of the ring 2 may be slightly lowered than a designed road surface. An area 10 enveloped with the rings 1 and 2 is filled up with sand or the like, thereby paving the area so that the finished part on the manhole cover 4 may be identical to the designed pavement height. Then, the paved area and the sand or the like inside the rings 1 and 2 are removed and a fastening nut for the receiving frame 5 is removed. The height of the receiving frame 5 and the cover 4 is adjusted to suit with the paved surface in the neighboring area and then fixed. Receiving frame height adjustment mortar 11 and a void filling mortar are applied which makes it possible to prevent a rubbing failure between the cover 4 and the road surface.