The purpose of the present invention is to provide an artificial ground freezing method having good coolant thermal efficiency without a gas-phase coolant being released into the ground or into the air. For that purpose, the present invention has: a freeze pipe (1: casing) for freezing the ground buried in the ground and a coolant circulation pipe (2) provided on the inside of the freeze pipe (1), wherein the coolant flowing inside the coolant circulation pipe (2) is carbon dioxide; and a coolant apparatus (10) that cools and supplies the carbon dioxide to the coolant circulation pipe (2), the coolant circulation pipe (2) comprising a first coolant circulation pipe (2A) on which a plurality of micro-coolant passages (2A delta) is formed, wherein the tip portion (tip portion in the ground) of the first coolant circulation pipe (2A) is connected to a plugging member (3: bottom socket) that connects the plurality of micro-coolant passages (2A delta) of the first coolant circulation pipe (2A) to a coolant supply side and coolant return side.