PURPOSE: To shorten the de-aerating time and increase the up-set velocity by abutting an end surface of container side of a die ring on a seal ring in a temporary stopping time of the container.

CONSTITUTION: A container tire 2, a container 1 and a container cylinder 33 are installed on an end platen 32. The air present between the container 1 and a billet 13 is made in vacuum before until beginning extruding the billet. At that time, the container 1 is stopped with a temporary stopping mechanism 30 before making the container 1 in contact with a die. An outer ring 10 is fixedly installed on the end surface of the die 3 side of the container tire 2. A seal ring 11 freely movable to the extruding direction and engaged impossibly detachable against the outer ring 10 is installed. The end surface of container 1 side of a die ring 5 to support with fitting the die 3 is constituted so as to freely contact with the seal ring 11 in the temporary stopping time of the container 1. Therefore, fear caused on the reverse flow of the air can be eliminated.