An object is to provide a method for manufacturing a resin laminate 100, the method being capable of achieving satisfactory reduction in weight and wall thickness while ensuring manufacture efficiency and product quality. To accomplish the object, a resin laminate manufacturing method includes a step of providing a pair of split mold blocks one of which has a cavity provided with a plurality of protrusions each extending toward the other one, and preparing two molten thermoplastic resin sheets each having a thickness adjusted, a step of feeding the two molten thermoplastic resin sheets between the pair of split mold blocks with a predetermined gap left therebetween such that each thermoplastic resin sheet protrudes around annular pinch-off parts, a step of forming a hermetic space between one of the sheets and the cavity of the one mold block opposed to an outer surface of the one sheet, a step of sucking air in the hermetic space from the one mold block side, pressing the outer surface of the one sheet against the cavity of the one mold block to shape the one sheet, and forming cup-shaped portions, and a step of clamping the pair of mold blocks, welding peripheral edges of the two molten thermoplastic resin sheets to each other, and welding the bottoms of the cup-shaped portions formed on the one sheet to an inner surface of the other sheet. According to this method, in the resin laminate thus manufactured, the two sheets are substantially equal in thickness to each other.