PURPOSE: To easily coat and repair a nail head at one touch by utilizing a penlike coater having a coating felt part impregnated with coating material to the tip and coating the nail head in the case of coating and repairing the nail head after a board for building is fastened to the substrate.

CONSTITUTION: After the boards 1 for building are fastened to a substrate 2, the heads of the nails 3 or the screws are coated and repaired. In this case, coating is performed by utilizing a penlike coater 4 having a coating felt part 5 impregnated with coating material to the tip. As a result, the heads of the nails and the screws or only the vicinities extremely near thereto are easily coated and repaired at one touch in board execution.