A hermetically-sealed compact case (1, 1b) capable of accommodating a cosmetic in a hermetically sealed state together with a cosmetic applicator, the compact case comprising: an inner tray to be filled with the cosmetic; a gasket (60,60,60c) configured to hermetically seal an inside space of the inner tray; a main case body having a vertically-flat box shape and having an open end at an upper side thereof; and a lid body configured to cover the open end side of the main case body openably and closably, wherein the main case body is provided with first (31,31b) and second frame portions formed side by side in a horizontal direction and configured to serve as spaces (3,4) for accommodating the inner tray and the cosmetic applicator, respectively, characterised in that the inner tray has a vertically-flat box shape and has an opening at one of upper and lower end faces thereof, by rotating about a hinge formed at a partitioning portion separating the first (31,31b) and second frame portions, the inner tray is invertible between an initial state of being accommodated in the first frame portion (31,31b) with the opening facing down and an inverted state of being accommodated in the second frame portion with the opening facing up, the gasket (60,60b,60c) has an end face facing a rim end face of the opening of the inner tray in the initial state, a pressing structure configured to bias the inner tray downward when the lid body is closed is formed between a bottom face of the inner tray in the initial state and a back face of the lid body, and in the initial state, the inner tray is biased downward by the pressing structure and is hermetically sealed by the gasket (60,60b,60c) when the lid body is closed. an inner tray to be filled with the cosmetic; a gasket (60,60,60c) configured to hermetically seal an inside space of the inner tray; a main case body having a vertically-flat box shape and having an open end at an upper side thereof; and a lid body configured to cover the open end side of the main case body openably and closably, wherein the main case body is provided with first (31,31b) and second frame portions formed side by side in a horizontal direction and configured to serve as spaces (3,4) for accommodating the inner tray and the cosmetic applicator, respectively, the inner tray has a vertically-flat box shape and has an opening at one of upper and lower end faces thereof, by rotating about a hinge formed at a partitioning portion separating the first (31,31b) and second frame portions, the inner tray is invertible between an initial state of being accommodated in the first frame portion (31,31b) with the opening facing down and an inverted state of being accommodated in the second frame portion with the opening facing up, the gasket (60,60b,60c) has an end face facing a rim end face of the opening of the inner tray in the initial state, a pressing structure configured to bias the inner tray downward when the lid body is closed is formed between a bottom face of the inner tray in the initial state and a back face of the lid body, and in the initial state, the inner tray is biased downward by the pressing structure and is hermetically sealed by the gasket (60,60b,60c) when the lid body is closed.