PROBLEM TO BE SOLVED: To provide Mn-Zn-Co ferrite having high initial relative permeability in a wide temperature range about from -20°C to 150°C.SOLUTION: The present invention provides Mn-Zn-Co ferrite that comprises FeO: 52.6-53.7 mol%, ZnO: 13.2-16.7 mol%, CoO: 0.15-0.50 mol% and the balance MnO as fundamental components, and also comprises SiO: 0.002-0.010 mass%, CaO: 0.005-0.060 mass%, NbO: 0.005-0.020 mass%, and MgO: 0.0020-0.0070 mass% as accessory components, with the balance inevitable impurities. In the inevitable impurities, a carbon content is reduced to 0.0050 mass% or less.