Bulk polycrystalline Sn0.95Fe0.05O2−σ and Sn0.93Fe0.05M0.02O2−σ (M = Sb/Mg) samples were fabricated. Detailed X-ray diffraction and transmission electron microscopy analyses revealed that the dopants most probably replaced the Sn in SnO2 structure, instead of forming impurity phase or nanocluster. By varying the dopant M (Sb/Mg), the electron- (Sb) and hole- (Mg) doping effect on the magnetic properties of Sn0.93Fe0.05M0.02O2−σ was investigated. Compared with Sn0.95Fe0.05O2−σ, the saturation magnetization decreased after doping with Sb and increased after doping with Mg. The changes of Fe oxidation state and carrier type, discovered from X-ray photoelectron spectroscopy, are believed to be responsible for the co-doping tuned ferromagnetism in Sn0.93Fe0.05M0.02O2−σ.