PURPOSE: To obtain a highly precision pattern even if a resist ink whose viscosity is lower than that of a usual one is used by making a surface roughness of a conductor in a resist pattern formation region extremely thinner than a minimum interval of a circuit pattern when forming a resist pattern by an ink jet head on a conductor.

CONSTITUTION: A board made of epoxy, polyester, polyimide, BT resin, heat resistant epoxy resin, OTFE or silicone resin to a glass cloth or a material integrally provided with a 1 to 50μm-thick metallic conductor such as copper, aluminum, gold, silver or platinum coated with a resin mentioned by using a metal such as aluminum, copper and iron as a core. The surface roughness of the conductor of the board is preferably 5/1000 or less, especially, 5/1000 or less and 5/10000 or more of a minimum interval of the circuit pattern. When the roughness of the conductor surface exceeds 5/1000 of a minimum interval of the resist pattern, the pattern precision lowers, disconnection and shortcircuiting are generated and the yield lowers.