Charge separation electric fields and magnetic fields induced by superthermal electrons escaped from plasmas have been evaluated using a very simple model. The magnitude and configuration of magnetic fields have been obtained. Generally, the circular-shaped magnetic fields are weak because of the charge separation electric field and the followed finite number of the escaped superthermal electrons, and they are mainly distributed in laser focus near the surface of the plasma because of the transverse motion of the escaped superthermal electrons. Only when the electron current is very strong (about kA through the cross-section with 1μm radius),can a megagauss magnetic field be obtained.