Provided is a drug supply unit which supplies solid drugs, said supply unit being provided with: 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, said support body guiding the drug supply body by sliding in a direction that intersects with the axial direction of the driving shaft portion, 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 drug supply unit is further provided with a retraction mechanism which retracts the driven engagement member in the axial direction so as not to interfere with the driving engagement member when the drug supply body is guided by sliding in relation to the support body.
