In Japan, the number of sudden death is estimated to be about 100,000/year and 60% of them are sudden cardiac death(SCD). And the cause of almost SCD is death of arrhythmia. The prevention of SCD by antiarrhythmic drugs is limited. So for the high risk group of SCD, ICD is needed. On the other hand, CPR of the bystander and the use of AED are important to avoid SCD. We must spread the education and training for the citizens.