A tablet cassette is provided that can easily adjust the width and depth etc. of a guide groove of a rotor depending on the size of a tablet to be dispensed. The tablet cassette includes a plurality of movable pieces 13 that are disposed movably in a radial direction of the rotor 3 in the plurality of tablet guide grooves 88 and form surfaces in the radial direction of the rotor 3 in the tablet guide grooves 88, and a movable piece moving mechanism 15 that moves the movable pieces 13 in the radial direction of the rotor 3. The tablet cassette also includes groove width adjustment mechanisms 17, 18, 19 that relatively move both sides of each of the tablet guide grooves 88 in the circumferential direction of the rotor 3.
