This invention relates to a hermetically sealed cosmetic container which accommodates volatile cosmetic material in a refill case detachably installed in a container housing. The hermetically sealed cosmetic container has: a container housing (12) of a receptacular shape having a bottom wall (12b) and an outer peripheral wall (12b) which define an accommodating space (18) therein; an outer lid (16) for opening and closing the accommodating space; a refill case (20) having an inner tray (28) with a cosmetic accommodating region (28a), an inner lid (30) for opening and closing the cosmetic accommodating region, a hinge mechanism (32) projecting outwardly from the inner tray for rotatably mounting the inner lid to the inner tray, and a hermetic sealing mechanism (38,40) disposed between the inner tray and the inner lid for hermetically sealing the cosmetic accommodating region, the refill case being detachably installed in one side (18a) of the cosmetic accommodating region, leaving a space (18b) in the other side; a groove (12d) defined in the outer peripheral wall portion of the container housing for fitting the hinge mechanism; a pair of slide guides (46) disposed horizontally on a pair of parallel side walls (18c, 18d) of the outer peripheral wall portion of the container housing; and a pair of slides (48) disposed in the inner tray of the refill case for being guided by the slide guides to slide the refill case in the accommodating space.