The invention relates to sealing apparatus and a method of a foam injection mold. The sealing apparatus of a foam injection mold that includes an upper mold that is disposed on an upper side as a movable mold to inject a core and a vacuum forming mold to form a skin. The upper mold and the vacuum forming mold are operated integrally and a lower mold is used during injection-molding and foaming of the core. A resilient sealing unit is integrally formed with the core when the core is injection-molded between the upper mold and the lower mold, to attach the core and the skin while the lower mold in which the core is formed and the vacuum forming mold in which the skin is formed are combined using a resilient restoring force. The resilient sealing unit seals a foaming space between the core and the skin.