An ablation needle device can maintain flexibility of an injection needle even when the length of an electrode constituted at a distal end portion thereof is increased and can perform cooling with small nonuniformity in the electrode during ablation. The ablation needle device includes: a hollow needle that is composed of a proximal end portion that is insulation-coated and a distal end portion constituting an electrode； a hub that includes a liquid injection port and a discharge port； an electric connector； a thermocouple； and cooling liquid introducing pipes each of which extends in the inside of the hollow needle, each of which has a distal end positioned in the inside of the distal end portion of the hollow needle, and each of which ejects liquid injected from the injection port from a distal end opening thereof.
