Porphyrin thin films were deposited by ionized cluster beam from a source material of tetraphenylporphyrin iron(III) chloride. It was found that the chlorine atoms are mostly removed from the original molecules during the film formation process, resulting in a film of tetraphenylporphyrin iron(II) complex. The film is chemically active and showed reversible reaction with O2 and CO gases at an elevated temperature. The formation of μ-oxo dimera, which hinders the chemical activity, was not observed. Electrical conductivity of the film was also measured under various atmosphere.