The present invention relates to an apparatus and a method of removing water contained in a gaseous material. An apparatus of removing water by phase-changing water contained in a gaseous material to a frost phase includes a gas inflow unit 100, a main body 200, a discharging unit 300, and a frost discharging unit 400. A method of removing water by phase-changing water contained in a gaseous material to a frost phase includes phase-changing water contained in gas to a frost phase, separating the phase-changed frost and the gas from which water is removed, discharging the gas from which the water is removed to the outside, and discharging the phase-changed frost to the outside.