The present invention relates to a therapeutic substance delivery device for delivering a therapeutic substance to a desired site in a bodily duct characterized in that the therapeutic substance delivery device is provided with: a therapeutic substance loading portion a connector which is connected to the therapeutic substance loading portion and a supplying/discharging pipe connected to the connector and in that the therapeutic substance loading portion includes a main body portion in which a recessed portion is formed a resilient film and a connecting pipe the connector is provided with a joint main body a flange portion fixed to the other end portion side of the joint main body and a fixing nut through which the joint main body passes the joint main body is provided with a tube fastening portion and at least part of the inner wall of the fixing nut is provided with a thread.
