  We investigate the stability of multiple-$Q$ spiral states in $d$-$p$
electron systems with the strong spin-charge coupling. By using variational
calculations on a square lattice, we find that the double-$Q$ state with the
scalar chirality density wave, which has been studied in the weak spin-charge
coupling regime, becomes the ground state even in the strong spin-charge
coupling regime by considering the effect of the $d$-$p$ hybridization. We also
show that the regions where the double-$Q$ state is stabilized are widely
extended for introducing the antiferromagnetic superexchange interaction
between nearest-neighbor localized spins.
