We perform 3D nested-grid radiation magnetohydrodynamic (RMHD) simulations of the formation of proto-stellar cores from molecular cloud cores with and without the Ohmic dissipation of magnetic fields. In the ideal RMHD models, the evolution of the protostellar core is very similar to that in the spherically symmetric non-rotating model due to the efficient angular momentum transport. However, if the resistivity presents, the angular momentum transport is considerably suppressed due to the loss of magnetic flux, and rotationally-supported circumstellar disks are rapidly built up in the vicinity of the protostellar cores. Magnetic fields are amplified by rotation and fast outflows are launched from the protostellar cores via magnetic pressure gradient force. To our knowledge, these are the first 3D RMHD simulations resolving the protostellar cores in the world.