Reirradiation is rarely applied to locally recurrent tumor in the previously irradiated region due to the expectation of severe side effects. Boron neutron capture therapy (BNCT) can deposit a large dose with a steep gradient between the tumor and surrounding normal tissues. We treated a patient with recurrent lung cancer in the previously irradiated chest wall with two-fractionated BNCT. In this case, most of the tumor regressed at seven months after the BNCT. No acute or late adverse events were observed. Locally re-recurrent tumor was found at the margin of the radiation field due to the inhomogeneous distribution of the neutron beam in the beam field. Although two-fractionated BNCT may be feasible for the treatment of locally recurrent shallow-seated tumors, especially from the view of palliation, attempts to improve the dose distribution should be considered.