Bystander CPR (cardiopulmonary resuscitation) is very important factor for OHCPA patients (out-of-hospital cardiopulmonary arrest), but the age of implementation of CPR training differs in each country. We evaluated the effect of education and investigated the proper age of introduction of CPR training after we gave a lecture of CPR training to elementary students (age 10-12). We evaluated 37 students who participated in our kids rescue competition. Their median weight was 34 (30-39) kg. The median depth of chest compression was 30 (25-34) mm. The median rate of compression was 124 (113-132) /min. The median rate of proper recoil was 89 (74-100) %. About the degree of comprehension, they couldn't get reaching point of check the security and breathing. According to the questionnaire, all parents understood how to provide CPR and had interests of first aid. We conclude that elementary students (age 10-12) can understand CPR training. However we need consideration for their physical aspect. We suggest that elementary students (age 10-12) are the proper age of introduction of CPR training.