Abstract: An apparatus and method of freezing a large volume of ground for tunnel construction and the like utilizing liquified nitrogen is described. The apparatus consists generally of a series of freeze pipes embedded in the ground, each of the freeze pipes consisting of a conductor tube and an inner header tube. The header tube of each of the succeeding freeze pipes in the series have discharge holes of a predetermined cross-section so that greater control of gaseous and liquified nitrogen pressure can be maintained throughout the system. By means of this method and apparatus more accurate control of ground freezing can be made by merely controlling the inlet liquified nitrogen pressure and the exhaust gaseous nitrogen temperature.