A drug delivery device (M) for subdividing and delivering a drug comprises: a cassette unit (1) capable of temporarily retaining a drug in the subdivided state, the cassette unit (1) being provided so as to be able to move between a home position and a withdrawn position； a cover (2) provided so as to be able to move between a closed position for covering the cassette unit (1) from above and an open position at which the cassette unit (1) is exposed； and a linking mechanism (3) for linking the operations of the cassette unit (1) and the cover (2). The linking mechanism (3) regulates the operation of the cover (2) so as to keep the cover (2) in the closed position when the cassette unit (1) is at the withdrawn position.
