Neutron-diffraction measurements have shown that the form of ErC0.6 that has a cubic, NaCl-type structure is paramagnetic above 90 K, exhibiting a free Er3+ moment. Below 90 K, ErC0.6 becomes a ferromagnet with a saturation moment of 2.5 Bohr magnetons (only 28% of the maximum free-ion moment), indicating a large crystal-field effect. By measuring the preferential crystallite orientation induced by the applied magnetic field, the direction of the ferromagnetically ordered moment was found to be parallel to the 〈100〉 axis. A ferromagnetic, short-range ordering coexists with the ferromagnetic long-range ordering at temperatures down to 1.6 K.