Escalation level of criminal act in Indonesia causing a lot of casuallities, and forcing people to defending them self more for their soul and life sake, even with violoence agains the agressor. The main problem is occasionally people not understand the concept of necessary defense it self. The purpose of this reserach aims to know how necessary defense it self are Regulated and applied in Indoensia based on Indonesia Penal Code. Studied from court judgment number 21/PID.B/2015/PN.Skg jo court judgment No 963 K/PID/2015. This research is normative research. Data used in this research are secondary data. Data collecting Technique used in this research is library research. The approach used is conceptual approach. Data analysis method used is qualitative method. The research results showed that the necessary defense are regulated in Indonesia Penal Code Article 49 Verse 1 and Verse and apllied based on the element of the verse itself. In deciding the result of the case District Court and Supreme Court Judges counting on Indonesia Penal Code Article 49 and it’s element for deciding is the accused guilty or not. The Judges then Decide that the accused are found proved for Homicide but are not found guilty, Because the homicide act that accused done is for defending himself and found suitbale with the conditions that are conduct in the element of Article 49 of Indonesia Penal Code