This research is caused by fidgetiness of author towards students less-critical thinking in learning process. To make this comes true; author tries to use debate method as tool or stimulus which is used for growing critical thinking ability. So that author formulates problem “How is a Debate Method Implementation in Developing Students Critical Thinking Ability on History Subject in XI Social 3 of 23 Senior High School?”. In this research, author uses Classroom Action Research combined with Kemmis & Mc. Taggart model. The activities which are done in this research are planning, acting, observing and reflecting. The subject of the research is students in class XI Social 3 of 23 Bandung Senior High School. Based on findings in field, after implementing debate method in History learning, class shown that there is positive changing in students’ critical thinking ability. Based on the four cycles performed, an improvement in critical thinking skills as increase as 314 points in second cycle and 519 points in third one. Based on description above, learning with debate method can upgrade critical thinking ability in History subject. This thing is proven in third cycle which is the peak of the research, in which students can reach critical thinking value with good and strongly good categories.