PURPOSE: To form an excellent bonding board for the following coating operation and the surface structure optimal for oxidization treatment without hardening the surface by grinding a surface of a metal sheet so as to provide multiple grooves for surface roughening, and giving the marking.

CONSTITUTION: Grooves 1, 3 extended practically in parallel with each other are formed by grinding or brushing, and multiple marking 5 are marked in the grooves by a marking roller 7. Depth of the marking nearly coincide with the mean depth of the grooves 1, 3, and centers of the marking coincide with cross points of parallel straight lines A1, A2, A3 arranged with an equal space and parallel straight lines B1, B2, B3 arranged with an equal space and extended at a certain angle, and the equal space of these straight lines is set at about 1-5 times of the longitudinal dimension of the marking 5.