In a mold press forming process for integrally molding a resin core member and a surface skin member, prior to the step of forming the resin core member, a surface skin member is retained between an upper die half and a lower die half by a surface skin retaining frame which consists of a fixed segment and a moveable segment. The moveable segment is moved vertically relatively to the fixed segment to better adapt the surface skin member to a three-dimensional parting line between the upper and lower half dies. When mounting the surface skin member onto the surface skin retaining frame presents a planar mounting surface, the mounting work is facilitated, and automated mounting devices can be used without any problem. Because the surface skin member can be stretched to a shape which approximately conform to the final shape of the laminated assembly by virtue of the moveable segment of the surface skin retaining frame, the surface skin member is prevented from being stretched excessively in localized parts thereof. Therefore, the surface skin member is prevented from being excessively thinned, whitened or ruptured during the molding process. Residual stress in the surface skin member is also minimized so that the molded laminated assembly is made free from warping which could be caused by excessive stretching of the surface skin member during the molding process.