The present invention relates to an airtight lip cosmetic case of which the inside is doubly sealed, comprising: a lower case; an upper case which is rotatably coupled to the top of the lower case and has a sealing shoulder formed on the outside thereof; a rising piston which rises within the upper case and has a lip cosmetic product attached to the upper side thereof; a sealing piston which is fixed and coupled to the outside of the rising piston; and an over-cap which is detachable from the lower case, wherein the airtight lip cosmetic case further comprises a sealing ring formed on the outer circumference of the rising piston such that the sealing ring rises in a state of being in close contact with the inner circumference of the upper case, and a sealing blade formed on the outer circumference of the sealing piston.