Abstract: A heat cycle injection compression molding method comprises several steps: heating a synthetic resin until it becomes fluidized; injecting the fluidized synthetic resin into a large and nonuniform cavity formed by a cavity block and a mold which is slightly opened; cooling the injected fluidized resin until the center portion temperature of the resin is equal to or lower than a solidifying temperature of the resin, thereby solidifying the resin; reheating the solidified resin uniformly until the temperature of the resin is higher than the solidifying temperature, thereby making the resin fluidized again; compressing the refluidized resin by reducing the volume of the cavities; cooling the refluidized resin until the temperature of the refluidized resin is lower than a take-out set temperature, while continuing the compressing step, thereby resolidifying the resin; stopping the compressing step; and ejecting out of the mold a formed product having a large and nonuniform thickness.