© Copyright owned by the author(s). The reaction cross section (σR) of the very neutron-rich carbon isotope 22C has been measured on a carbon target at 235 MeV/nucleon. A σR of 1.280 ± 0.023 b was obtained for 22C, significantly larger than those for the neighboring isotopes, supporting the halo character of 22C. A 22C root-mean-squared matter radius of 3.44±0.08 fm was deduced using a four-body Glauber reaction model. This value is smaller than an earlier estimate of 5.4±0.9 fm derived from a σR measurement on a hydrogen target at 40 MeV/nucleon.