A method of manufacturing a multilayer wiring board according to the present invention comprises the step of heating and pressurizing a stacked product to be integrated in a state in which a plurality of double-sided wiring boards (10) having a wiring pattern (12) formed on both surfaces of an insulating layer (11) are laminated through a prepreg (1) obtained by impregnating a resin porous film with a thermosetting resin. The present invention is advantageous to mass production because a gap for forming an insulating layer can easily be controlled, and furthermore, can provide thinner layers of the whole board and is also advantageous to the flattening of the surface of the board.