An ablation needle device is a needle device intended for an ablation treatment of an adrenal tumor with transvenous introduction of an injection needle into an adrenal gland. The ablation needle device includes a metal injection needle including a pointed tubular distal portion and a tubular proximal portion, and a grip portion attached to a proximal side of the injection needle. The proximal portion of the injection needle is given flexibility by forming a helical slit in a distal region of the proximal portion. An outer surface of the proximal portion is coated with resin. A distal end of the distal portion of the injection needle is closed. A plurality of fine holes are formed in an outer surface of the distal portion including the closed part. The grip portion has a liquid-injection port for supplying liquid into the lumen of the injection needle.
