PURPOSE: To contrive molding of a product which secures a uniform flow at a product part and has neither a warp nor a twist, by a method wherein at the time of molding of a thin molded board for a solid wiring board, a tab becoming a resin rich area is provided at a final filling part facing a film gate.

CONSTITUTION: In a product part 1 molding a thin board, a film gate 2 is provided in its long side direction and resin circulated through the gate 2 is received by a tab 3 as a resin receipt at an end part of the circulation. Hereby, a resin flow at the product part 1 is kept uniform and the product part 1 is prevented from generating a warp or a twist. Then, after the resin of the product part 1 is cured, the tab 3 and gate 2 are cut off, the product part 1 becomes a molded product, even a thin product can be filled with the resin having a fixed circulating direction and neither a warp nor a twist are generated.