PURPOSE: To easily manufacture a grid with a high active-material-holding ability by giving cuts on a rolled sheet made of a lead alloy, by means of a blade having a thick part provided with projections and indentations, before the sheet is expanded so as to form grid bones, and at the same time, by providing the grid bones with projections and indentations.

CONSTITUTION: A rolled sheet 1 made of lead or a lead alloy is given cuts by moving a blade 2 up and down, while being shifted continuously in the direction perpendicular to the blade 2. After that, the sheet 1 is cut into necessary size, thus a grid is obtained. During the time when the rolled and cut sheet 1 is expanded with the blade 2 having irregularities so as to form meshes 5, since a thick part 3 of the blade 2 is provided with numbers of irregularities 4, projections and indentations are provided on grid bones 6 of the grid by means of the irregularities 4.