PURPOSE: To improve a drill straight-drive property and a boiling heat resistance by forming an inner-layer material and an outer-layer material including a specific nonwoven fabric in one piece through a resin layer including a specific nonwoven cloth.

CONSTITUTION: An external-layer material is provided and formed in one piece on the upper surface and/or lower surface of a required number of inner-layer materials including a glass nonwoven fabric through a resin layer including the glass nonwoven fabric. The inner-layer material consists of an electrical circuit which is formed on a single-surface or a double-surface metal-clad laminated plate consisting of a resin such as a phenol resin, a cresol resin, an epoxy resin, and a fluoric resin, an inorganic fiber such as glass and asbestos, an organic synthetic fiber such as polyester, a natural fiber such as cotton, and paper base. But, the glass nonwoven fabric always needs to be used for the base. It is desirable to add a filling agent such as alumina, silica, talc, synthetic resin chip, pulp, and cotton powder to a resin which is dipped into the resin. A single-side metal foil clad laminated plate which is obtained by dipping resin into a base including at least one glass nonwoven fabric is used as the outer-layer material. Individuals such as copper and aluminum or their alloy are used as a metal foil.