A mold set is installed that consists of a male mold and a female mold having on its inner surface side a predetermined embossing pattern and predetermined vacuum suction fine holes. A vacuum suction mechanism for feeding a vacuum pressure to the vacuum suction fine holes comprises a receiving hole disposed at right angles with the reference plane for the mold with its front end extending toward the inner surface of the female mold over a distance less a predetermine distance, and having a predetermined diameter, and vacuum suction fine holes linearly extending from adjacent the front end of the receiving hole toward the inner surface of the female mold and consisting of a hole disposed at plane right angles with the inner surface of the female mold, holes radially disposed around the hole disposed at plane right angles, and so on. A spacer for controlling the cavity space to a suitable volume is installed at a guide pin along which the female and male molds slide-wise engage each other.