A drug delivering apparatus includes a drug container, a pre-filled syringe including a cylindrical container having a nozzle portion and an injection needle attachment portion, and a connecting tool configured to allow communication between the inside of the cylindrical container and the inside of the drug container. The connecting tool further includes a nozzle insertion portion. The pre-filled syringe further includes a cap member configured to be detachably fitted on the injection needle attachment portion, the cap member having an opening into which the nozzle insertion portion can be inserted. The injection needle attachment portion has a guiding groove in the inner periphery thereof. In the state where the cap member is fitted on the injection attachment portion, at least a part of the edge of the opening is located on the inner side relative to the bottom portion of the guiding groove.
