PURPOSE: To obtain a substrate on which metallic foil of a nuiform thickness can be formed by electroless plating by coating in advance a laminated material with a catalyst and impregnating resin contg. a catalyst into the laminated material.

CONSTITUTION: A laminated material of a porous substance such as paper, glass fiber or polyester fiber is coated with a catalyst such as Pd, Au or Ag by spraying or other method. The laminated material is laminated by an arbitrary number of sheets as required, and the resulting laminated body is dipped in resin contg. a catalyst to obtain a substrate. The catalyst can be dispersed nearly uniformly in the laminated material. When electroless plating is carried out after piercing a hole in the substrate, metallic foil of a uniform thickness can be formed on the peripheral wall of the hole.