To decrease the moisture absorption and the thermal dimensional change of a nonwoven fabric for electric insulation containing a wholly aromatic polyester fiber, improve the moisture resistance and heat resistance and decrease the thermal expansion coefficient in thickness direction of an insulation layer produced by applying a thermosetting resin to the nonwoven fabric for electric insulation.

The nonwoven fabric for electric insulation is produced by using a wholly aromatic polyester fiber treated its surface with a resol phenolic resin to form a completely cured film of the phenolic resin. The resol phenolic resin is preferably a water-soluble low-molecular resol phenolic resin having large amount of residual methylol groups. The laminated plate or the insulation layer of a printed circuit board is produced by impregnating an epoxy resin in the nonwoven fabric for electric insulation and hot-pressing the impregnated product.