The neutron irradiation system for boron neutron capture therapy (BNCT) using compact accelerators installed at hospitals was mainly investigated for the usage of direct neutrons from near-threshold 7Li(p,n)7Be, and moderated neutrons from 2.5 MeV 7Li(p,n)7Be reactions and other reactions. This kind of system can supply the medical doctors and patients with convenience to carry out BNCT in hospitals. The accelerator system would be regarded as the next-generation of BNCT in the near future.