Palladium acetate was sublimed at reduced pressure at 400 degrees C and was evacuated through the porous wall of an alpha-alumina support tube. A thin palladium membrane was thus formed in the macropores due to chemical vapor deposition. The palladium membrane showed a hydrogen permeance of 10(-6) mol . m(-2). s(-1). Pa-1 and a hydrogen/nitrogen permselectivity higher than 1000. Further, gallium-silicate catalyst (Si/Ga = 40) was synthesized via an alkoxide method, and the membrane was coaxially fixed in a tubular reactor in which the catalyst particles were packed. Aromatization of propane was performed at 500-600 degrees C, and the hydrogen evolved was continuously removed from the system. Propane conversion and aromatics selectivity were increased by decreasing hydrogen partial pressure by the installation of the membrane.