The cubic perovskite structure was stabilized in solid solution of SrFeO₃ and SrNiO₃. The compounds were obtained by high pressure synthesis and contained high valence state of Fe⁴⁺ and Ni⁴⁺ ions in the corner-sharing oxygen octahedra. SrFe_1−xNi_xO₃ with x = 0.4 and 0.5 showed ferromagnetic-like behaviors at room temperature, in contrast to the end member perovskite SrFeO₃ (x = 0) with helical antiferromagnetism (T_N = 134 K). Ni substituton for Fe in the cubic antiferromagnetic SrFeO₃ induced the ferromagnetism.