Abstract: A portable tumbler comprises: a lower cup portion having an open top surface and an accommodation space formed therein; a lower connection portion coupled to the outer circumferential surface of the lower cup portion; an upper cup portion having open top and bottom surfaces and a prescribed height; an upper connection portion coupled to the outer circumferential surface of the upper cup portion and detachably coupled to the lower connection portion; and a cap coupled to the upper cup portion so as to cover the open top surface of the upper cup portion, wherein the lower connection portion and the upper connection portion may be coupled to each other so that the upper end of the lower cup portion and the lower end of the upper cup portion are in contact with each other.