Removal of non-metallic and metallic impurities from neodymium and lanthanum has been examined by the electron beam floating zone melting (EBFXM) technique in a high vacuum. The carbon and sulfur contents are found to be reduced by their redistribution caused by the zone pass, while the reduction of oxygen and nitrogen contents are scarcely observed for neodymium. Metallic impurities having vapor pressures higher than neodymium and lanthanum, such as calcium and magnesium, can be removed through the vaporization. On the other hand, iron, silicon and copper can be redistributed during zone passes. The residual resistivity ratios of neodymium and lanthanum increase after the EBFZM as a result of the reduction of respective impurities.