A high-quality polycrystalline sample of the correlated 4d post-perovskite CaRhO3 (Rh4+: 4d(5), S-el = 1/2) was attained under a moderate pressure of 6 GPa. Since the post-perovskite is quenchable at ambient pressure/temperature, it can be a valuable analogue of the post-perovskite MgSiO3 (stable higher than 120 GPa and unstable at ambient pressure), which is a significant key material in earth science. The sample was subjected for measurements of charge-transport and magnetic properties. The data clearly indicate it goes into an antiferromagnetically ordered state below similar to 90 K in an unusual way, in striking contrast to what was observed for the perovskite phase. The post-perovskite CaRhO3 offers future opportunities for correlated electrons science as well as earth science.