A resin sheet production method includes a preparation step of preparing a resin molding sheet including a base and a thermally expansive layer that is formed on one main surface of the base, the thermally expansive layer including a thermally expandable material; a heat conversion layer forming step of forming a heat conversion layer that converts electromagnetic waves to heat on at least one of the first main surface of the resin molding sheet or a second main surface on a side opposite to the first main surface; a pre-heating step of heating the resin molding sheet on which the heat conversion layer is formed to a temperature that is lower than an expansion starting temperature at which the thermally expandable material starts to expand; and a main heating step of irradiating the heat conversion layer of the resin molding sheet that is heated in the pre-heating step with the electromagnetic waves to cause the heat conversion layer to distend, thereby causing the base to deform and forming a shaped object on the resin molding sheet.