PURPOSE: To easily obtain an accurate ground board with projections by a method wherein a kneading material is filled in a frame body sightly beyond the top surface of the frame body under the condition that a plate, in which holes having the predetermined depth are formed at the predetermined intervals, is laid on the bottom part of the rectangular frame body and then pressed down to be flush with the top surface of the frame body and, after curing demolded.

CONSTITUTION: A frame body 9 consists of an outer frame 91 and a bottom frame 92. A perforated plate 94 is laid through a bottom sheet 93 on the bottom frame 92. Holes 94a pass through the perforated plate 94 and are blocked by the bottom sheet 93. A kneading material is filled in the frame body slightly beyond the top surface of the frame body 9 and then pressed down with a roll or the like to be flush with the top surface of the frame body 9 so as to fill the kneading material even in the holes 94a. After that, the kneading material is stream-cured and dried. During drying, the frame body 9 is separated from the kneading material so as to obtain a ground board as a product.