PURPOSE: To obtain a laminated sheet for electrical use having a low degree of roughness in the surface by applying continuous, zero pressure heating to a laminated and cutting it to a prescribed dimension, where the laminate is prepared as follows: a non-woven fabric in a continuous length is impregnated with a resin containing a mineral filler, a glass cloth of continuous length impregnated with another resin having a greater rate of cure is stretched on the top surface and under side of the resin impregnated non-woven fabric and a metal foil of continuous length is further laid on top of the same top surface and underside.

CONSTITUTION: A 0.5mm thick non-woven glass fabric is impregnated with an unsaturated polyester resin containing 100wt.% of aluminum hydroxide to obtain a resin-impregnated non-woven fabric base material having a resin content of 45%. A resin impregnated glass cloth base material having a resin content of 45% is also prepared by impregnating a 0.12mm thick glass cloth with an unsaturated polyester resin wherein 1 part of dicumyl peroxide is added to 100 parts of unsaturated polyester resin. One piece each of the resin impregnated glass cloth base material is laid on the top surface and the underside of the resin impregnated non-woven fabric base material. Furthermore, as the outermost layer thereof, a 0.035mm thick copper foil with a bonding adhesive is stretched with the side of bonding adhesive inward, and the so obtained laminate is subjected to zero pressure heating at 140°C for 20 minutes and then severed according to a prescribed dimension to obtain a 0.8mm thick laminated sheet having a double-side coating of copper.