Drug infusion needle and drug infusion method

A drug transferring needle comprising:

• a needle base portion attached to a tubular end of a syringe;
• a tubular portion adjacent to the needle base portion;
• a first needle portion which is covered with the tubular portion and has therein an air passage in which one end and an other end are exposed from the tubular portion to outside;
• and
• a second needle portion which is covered with the tubular portion and has therein a liquid passage,
• wherein the second needle portion is longer than the first needle portion, an axial direction of the first needle portion and an axial direction of the second needle portion being parallel,
• wherein when a portion which includes the second needle portion having a liquid pass opening of the liquid passage is a distal end, a portion which is arranged adjacent to the distal end and includes the tubular portion and the second needle portion is an intermediate portion, and a portion which is arranged adjacent to the intermediate portion and includes the tubular portion, the second needle portion, and the first needle portion is a base portion, a diameter of the intermediate portion is larger than a diameter of the distal end, and the diameter of the intermediate portion is smaller than a diameter of the base portion.