A cartridge configured to be mounted on a tape printer, the cartridge includes a ribbon roll around which an ink ribbon is wound, and a cartridge case configured to accommodate a tape roll around which a tape is wound and that accommodates the ribbon roll, in which the cartridge case includes a third case portion, a first case portion that constitutes a tape roll accommodating portion accommodating the tape roll between the first case portion and the third case portion, and a second case portion that is separated from the first case portion and accommodates the ribbon roll between the second case portion and the third case portion, and the first case portion is configured to open and close the tape roll accommodating portion.