The effect of chlorine species on diamond deposition with chlorobenzenes as carbon sources was investigated. Diamond deposited from an Ar/chlorinated benzenes/H-2 plasma jet, on which Cl species were adsorbed, was exposed to Ar and Ar/H-2 plasma jets and diamond deposited from an Ar/C6H6/H-2 plasma jet, on which H species were adsorbed, was exposed to an Ar/CCl4 plasma jet. During the exposure, HCl species were observed in the plasma jets by means of optical emission spectroscopy. By the exposure of samples to the Ar/H-2 and Ar plasma jets, adsorbed Cl species disappeared. By the exposure of the H adsorbed sample in the Ar/CCl4 plasma jet, the surface was covered with graphite or amorphous carbon. The abstraction of surface adsorbed Cl species by H atoms, the dehydrochlorination reaction on the surface and the abstraction of surface adsorbed H species by Cl species would occur in the diamond deposition from the plasma jets with chlorobenzenes as carbon sources. Excess amounts of Cl species would foster the nondiamond deposition.