For basic research experiments of accelerator driven subcritical reactor (ADSR) system, an 150 MeV FFAG accelerator is now constructed in Kyoto University Research Reactor Institute (KURRI). The installed accelerator will be connected to the nuclear fuel assembly and be used for physical and chemical research using the proton beam produced by the accelerator. The highly secure and flexible interlock system is required for such a gradual developed complex. The interlock system constructed by using PC and PLC (Programmable Logic Controller) is an adequate system because of their high reliability and flexibility.