The delivery system has a supply device having a supply port for supplying an article; a receiving device having a receiving port that is able to receive the article that is supplied from the supply port; and a detection unit that is capable of detecting: a first state in which the supply device and the receiving device are joined by the supply port engaging with the receiving port; a second state in which the supply device and the receiving device are close together and there is a space between the supply port and the receiving port; and a third state in which the supply device and the receiving device are separated and the space between the device is wider than in the second state.