In order to separate the Freon-12 and air mixture$(CF_2Cl_2/Air=0.1/99.9 vol.%)$ by pressure swing adsorption (PSA), the breakthrough curve was experimentally observed in a fixed bed adsorption column. A single adsorber was packed with various adsorbents such as, the activated carbon(S-AC, W-AC) and the molecular sieve(MS-5A, MS-13X). The order of appearance of breakthrough curve is MS-5A > MS-13X > W-AC > S-AC. The activated carbon was found to be more effective adsorbent for separating Freon-12 from the mixture than the molecular sieve was. From the experimental data obtained by the separation of Freon-12 gas out of the air stream in the steady-state PSA process cycle, whose size is the same one of column used for the breakthrough curve observation, it has been confirmed that Freon-rich gas could be obtained from the purge step of PSA and Freon-free air could be obtained from the adsorption step of PSA cycle.