A tablet cassette, comprising: a cassette body formed with a tablet receiving section for receiving a tablet; a rotor rotatably driven and disposed in a bottom of the tablet receiving section of the cassette body, an outer peripheral surface of the rotor being formed with a plurality of guide grooves extending in an axial direction and a circumference groove extending in a circumferential direction; and a partitioning member attached to the cassette body, the partitioning member entering the guide groove of the rotor that comes to a position where the guide groove communicates with a tablet outlet provided in the cassette body, wherein a side wall of the cassette body is formed with a plurality of slits along the axial direction of the rotor, to which a partitioning portion of the partitioning member is inserted, the slits extending in the circumferential direction of the rotor, characterized in that the tablet cassette further comprises: a retention member configured to retain the partitioning member and to adjust a retention position of the partitioning member so as to change an entrance depth of the partitioning member to the guide groove of the rotor, and an adjustment member configured to attach the retention member retaining the partitioning member and to adjust an attachment position of the partitioning member such that the partitioning portion of the partitioning member is inserted to one of the plurality of the slits to change a height of the partitioning member. a cassette body formed with a tablet receiving section for receiving a tablet; a rotor rotatably driven and disposed in a bottom of the tablet receiving section of the cassette body, an outer peripheral surface of the rotor being formed with a plurality of guide grooves extending in an axial direction and a circumference groove extending in a circumferential direction; and a partitioning member attached to the cassette body, the partitioning member entering the guide groove of the rotor that comes to a position where the guide groove communicates with a tablet outlet provided in the cassette body, wherein a side wall of the cassette body is formed with a plurality of slits along the axial direction of the rotor, to which a partitioning portion of the partitioning member is inserted, the slits extending in the circumferential direction of the rotor, characterized in that the tablet cassette further comprises: a retention member configured to retain the partitioning member and to adjust a retention position of the partitioning member so as to change an entrance depth of the partitioning member to the guide groove of the rotor, and an adjustment member configured to attach the retention member retaining the partitioning member and to adjust an attachment position of the partitioning member such that the partitioning portion of the partitioning member is inserted to one of the plurality of the slits to change a height of the partitioning member. a retention member configured to retain the partitioning member and to adjust a retention position of the partitioning member so as to change an entrance depth of the partitioning member to the guide groove of the rotor, and an adjustment member configured to attach the retention member retaining the partitioning member and to adjust an attachment position of the partitioning member such that the partitioning portion of the partitioning member is inserted to one of the plurality of the slits to change a height of the partitioning member.