PURPOSE: To produce a laminated sheet having good dimensional stability, excellent water resistance and electrical properties, by laminating specified paper substrates impregnated with a thermosetting resin and heating the laminated substrates under pressure.

CONSTITUTION: A laminated sheet used in the production of printing circuit boards is formed by impregnating paper substrates, density 0.4W0.6g/cm3, containing 100W20wt% of unbleached pulp of conifer, (about up to 20wt% of unbleached pulp of broadleaf trees can be contained.) with a thermosetting resin such as a resin obtained by reacting a phenol with formaldehyde; then laminating a plurality of these substrates; and heating the laminated substrates under pressure to integrate them into one body.