Neutron sources driven by electron accelerators have opened up the possibilities of pulsed-neutron beam experiments for material science. Neutrons are generated by a heavy metal-target with the pulsed electron beam. In the target, γ-rays of electromagnetic showers excite nuclei of the metal and fast neutrons are generated through the evaporation process. The fast neutrons are slowed down in a moderator, which is made of ambient water, polyethylene, or solid methane or mesitylene at about 20 K and pulsed thermal or cold neutron beam is extracted. Hokkaido University neutron source (HUNS) is one of the earliest electron accelerator driven neutron sources, that was used to develop various cold and thermal neutron sources and still actively used for material science.