Abstract: A composite core is selected which is formed of a reinforcing fiber and a thermoplastic synthetic resin by a compression molding, and including a first region in which the grammage M.sub.1 is set in a range of 400 g/m.sub.2 .ltoreq.M.sub.1 .ltoreq.700 g/m.sup.2 to provide a reduction in weight, and a second region in which the grammage M.sub.2 is adjusted in a range of 900 g/m.sup.2 .ltoreq.M.sub.1 .ltoreq.1,200 g/m.sup.2 to provide an enhanced rigidity. At a first step, the composite core is heated, whereby it is expanded, and the thermoplastic synthetic resin is expanded. At a second step, a skin material is superposed onto the composite core. At a third step, the composite core is compressed, and the skin material is bonded to the composite core. In the laminate produced in the above manner, the first region contributes to a reduction in weight, and the second region contributes to an increase in rigidity.