Provided is a drug supply unit which supplies solid drugs, said supply unit comprising: a drug supply body having a drug accommodating portion that accommodates a drug, and a driven shaft portion that is provided so as to be rotatable in relation to the drug accommodating portion, and supplying a drug from the drug accommodating portion through rotational driving of the driven shaft portion and a support body having a rotational drive source, and a driving shaft portion that is coaxially connected to the driven shaft portion, and is rotationally driven by the rotational drive source, and supporting the drug supply body while being detachable therefrom. The driven shaft portion has a driven shaft portion body, and a driven engagement member that can be moved in relation to the driven shaft portion body in the axial direction. The driving shaft portion has a driving shaft portion body and a driving engagement member that is fixed to the driving shaft portion body and engages with the driven engagement member. The driven engagement member is biased in the proximal direction so as to approach the driving engagement member. The drug supply unit is further provided with a rotation prevention portion which allows rotation of the driven engagement member when the drug supply body is mounted on the support body but prevents rotation of the driven engagement member when the drug supply body is separated from the support body.
