We study the resonant x-ray scattering ͑RXS͒ spectra of CeB 6 in an antiferroquadrupole ͑AFQ͒ ordering phase, near the Ce L 3 edge under the applied magnetic field H ʈ ͑1 ,1,0͒. On the basis of a localized electron model equipped with a mechanism that the RXS signal is brought about by the intra-atomic Coulomb interaction in Ce, we calculate the RXS spectra. The obtained spectra exhibit two contributions around the electric dipole ͑E1͒ and quadrupole ͑E2͒ positions, and differ drastically when the orientation of H is reversed. The difference is brought about by the cross terms between the even-rank AFQ and magnetic-induced odd-rank contributions. At the E1 region, the relevant cross term is the one within the E1 process, while at the E2 region, they are ones within the E2 process and between the E1 and E2 processes. These findings capture the characteristic features the recent experimental data show, and provide a strong support and information of the field-induced multipole orderings. We also evaluate the RXS spectra near the L 2 edge. Though the results show no E2 contribution, we find that the intensity around the E1 transition, which is as large as that at the L 3 edge, can be detected experimentally.