A magnetic core includes alloy phases 20 each made of Fe-based soft magnetic alloy grains including M1 (wherein M1 represents both elements of Al and Cr), Si, and R (wherein R represents at least one element selected from the group consisting of Y, Zr, Nb, La, Hf and Ta), and has a structure in which the alloy phases 20 are connected to each other through a grain boundary phase 30. In the grain boundary phase 30, an oxide region is produced. The oxide region includes Fe, M1, Si and R and further includes Al in a larger proportion by mass than the alloy phases 20.