Tritium compounds need to be separated to each chemical form for reasonable and continuous monitoring of tritium compounds. In this study, the continuous monitoring of HT in the air containing HT and HTO was investigated using the separation cell made of porous Vycor glass tube. The apparatus for a continuous and selective monitoring of tritium compounds in the air containing HT and HTO was constructed of radioactive gas monitor, ion chamber and the separation cell. An air containing tritium compounds (HT, HTO, etc.) was provided by Research Reactor Institute of Kyoto University. In the air containing of HT and HTO, HT is found to permeate selectively through the pores of the porous Vycor glass tube wall.