CeRh 2Si 2 shows two successive antiferromagnetic phase transitions. Recent neutron scattering experiments on single-crystalline sample suggest that the ground state is a 4- q superimposed structure. However, the actual ground-state magnetic structure has not been determined without ambiguity up to now. Moreover, the absolute values of the ordered moments are quite different between NMR and neutron measurement. Zero-field (ZF) and longitudinal-field (LF) μSR experiments were performed to investigate this novel ground-state magnetic structure. The ground state magnetic structures and absolute values of the ordered moments will be discussed with the help of neutron scattering results.