A drug supply device includes an elongate shaft, a drug holding sheet attached to a distal of the shaft and having a first face that is directed to the front of the shaft when the drug holding sheet is developed and has drug held thereon and a second face that is directed to a proximal side of the shaft, the drug holding sheet further having a plurality of folded portions capable of being folded such that the first face is positioned on the inner side, and a development member disposed on the second face of the drug holding sheet and deformable to develop the plurality of folded portions of the drug holding sheet. The drug supply device supplies the drug held on the first face of the drug holding sheet in a state in which the development member is deformed to develop the plurality of folded portions.
