The effects of the K−K interactions on properties of the multi‐antikaonic nuclei (MKN), in which several K− mesons are embedded to form deeply bound states, are investigated based on chiral symmetry combined with the relativistic mean‐field theory. The K−K interactions originate from two contributions: One is the contact interaction between antikaons inherent in chiral symmetry, and the other is the one generated through coupling between the K− and meson mean fields. It is shown that the former leads to saturation of not only nuclear density profiles but also the strength of the K− field at the center of the MKN and that both parts of the K−K repulsive interactions have a large contribution to the ground state energy of the K− mesons and binding energy of the MKN as the number of the embedded K− mesons increases.
