  The binding energy differences of the valence proton and neutron of the
mirror nuclei, $^{15}$O -- $^{15}$N, $^{17}$F -- $^{17}$O, $^{39}$Ca --
$^{39}$K and $^{41}$Sc -- $^{41}$Ca, are calculated using the quark-meson
coupling (QMC) model. The calculation involves nuclear structure and shell
effects explicitly. It is shown that binding energy differences of a few
hundred keV arise from the strong interaction, even after subtracting all
electromagnetic corrections. The origin of these differences may be ascribed to
the charge symmetry breaking effects set in the strong interaction through the
u and d current quark mass difference.
