An object of the present invention is to provide a medical device which absorbs a difference in dimension between the members, can be applied to an existing device without generating a dead space in a flow path of a therapeutic substance when administrating the therapeutic substance, and is high in versatility. The medical device 1 of the present invention comprises a feeding member 2, a connected member 3 and a joint member 4, and the joint member 4 comprises an inner tapered portion 42 and an outer tapered portion 43, wherein the joint member 4 is configured so that the tip end T of the joint member 4 is located on the inner tapered connecting portion 32 when the joint member 4 is connected to the hub 33.
