As a countermeasure for eavesdroppers in wireless communications, a secret key agreement scheme using a variable directional antenna called ESPAR antenna was developed. In this scheme, the process of information reconciliation is necessary to correct the discrepancies between the legitimate users’ keys. In this paper, we propose a new information reconciliation protocol using the reliability of the raw keys. The proposed information reconciliation protocol is a modified version of the protocol used in quantum key distribution called Cascade. The results of simulations show that the proposed protocol can correct errors with less the number of disclosed bits and less the number of communications than those of Cascade.