A theoretical study has been made on the one-dimensional transient system in which two-component (condensable and noncondensable) gas mixture flows through a porous medium with condensation and evaporation. The governing equations were carefully formulated minimizing prerequisite assumptions such as the local thermal equilibrium. The calculation domain was divided into four regions in the light of the relationship between the gas and porous medium temperatures, and the volume fraction of the condensed liquid. The numerically calculated results have successfully demonstrated the features of temperature variations and the propagations of the condensation, evaporation and drying fronts. Further discussions have been also conducted to gain insights into the detailed heat and mass transfer mechanisms.