PURPOSE: To flatten the installation of a pattern and to form the pattern in a multilayer by laminating metal layers by anodizing a metal film formed on a board, and providing an insulating layer and the pattern at predetermined positions.

CONSTITUTION: An electrode laser 2 is laminated on one side surface of a board 1, a first metal layer 4 is laminated on the other side surface, a resist mask 5 is provided at a predetermined position of the layer 4, anodized to form an insulating layer 6, and a first metal layer pattern 4A is formed. A second metal layer 7 is laminated, similarly anodized to form the layer 6 at a predetermined position, and a second metal layer pattern 7A is formed. With this structure, the alternate lamination of the insulating layer and a conductor layer is not required. The patterns 4A, 7A can be formed without bending the installation of the pattern to simplify the steps and to flatten the pattern.